640.求解方程 其他实现

JavaScript/my_leetcode.js

@@ -5,7 +5,7 @@
  * @return {number}
  * @see https://leetcode-cn.com/problems/xor-operation-in-an-array/
  */
-var xorOperation = function (n, start) {
+const xorOperation = function (n, start) {
     return (start & 3) < 2 ? ((n & 1) === 0) ? (n & 3) : (start + 2 * n - 3 + (n & 3)) : ((n & 1) === 0) ? ((start + (n - 1) * 2) ^ (start - 2 + (n & 3))) : (start + 1 - (n & 3));
 };
 
@@ -15,7 +15,7 @@ var xorOperation = function (n, start) {
  * @return {number}
  * @see https://leetcode-cn.com/problems/sqrtx/
  */
-var mySqrt = function (x) {
+const mySqrt = function (x) {
     const xHalf = 0.5 * x;
     let i = new BigInt64Array(new Float64Array([x]).buffer)[0];
     i = 0x1FF7A3BEA91D9B1Bn + (i >> 1n);
@@ -30,6 +30,6 @@ var mySqrt = function (x) {
  * @param {number[]} nums
  * @return {number}
  */
-var missingNumber = function(nums) {
+const missingNumber = function (nums) {
     return [nums.length, 1, nums.length + 1, 0][nums.length & 3] ^ nums.reduce((o, n) => o ^ n, 0);
 };

JavaScript/q0604.js

@@ -0,0 +1,42 @@
+/**
+ * 640.求解方程
+ * @param {string} equation 方程式
+ * @return {string} 解
+ * @see <a href="https://leetcode-cn.com/problems/solve-the-equation/">原题链接</a>
+ */
+const solveEquation = function (equation) {
+    let a = 0, b = 0, c = 0, sign = 1, left = 1, hasC = false;
+    for (let z of equation) {
+        switch (z) {
+            case 'x':
+                a += hasC ? sign * left * c : sign * left, c = 0, hasC = false;
+                break;
+            case '+':
+                b += sign * left * c, c = 0, sign = 1, hasC = false;
+                break;
+            case '-':
+                b += sign * left * c, c = 0, sign = -1, hasC = false;
+                break;
+            case '=':
+                b += sign * left * c, c = 0, sign = 1, left = -1, hasC = false;
+                break;
+            default:
+                c = c * 10 + (z - '0'), hasC = true;
+                break;
+        }
+    }
+    b += sign * left * c;
+    if (a === 0 && b === 0) {
+        return "Infinite solutions";
+    } else if (a === 0) {
+        return "No solution";
+    } else {
+        return "x=" + -b / a;
+    }
+};
+
+console.assert(solveEquation("x+5-3+x=6+x-2") === "x=2");
+console.assert(solveEquation("x=x") === "Infinite solutions");
+console.assert(solveEquation("2x=x") === "x=0");
+console.assert(solveEquation("0x=0") === "Infinite solutions");
+console.assert(solveEquation("0=0x") === "Infinite solutions");

TypeScript/q0604.ts

@@ -0,0 +1,36 @@
+function solveEquation(equation: string): string {
+    let [a, b, c, sign, left, hasC] = [0, 0, 0, 1, 1, false];
+    for (let z of equation) {
+        switch (z) {
+            case 'x':
+                [a, c, hasC] = [a + (hasC ? sign * left * c : sign * left), 0, false];
+                break;
+            case '+':
+                [b, c, sign, hasC] = [b + sign * left * c, 0, 1, false];
+                break;
+            case '-':
+                [b, c, sign, hasC] = [b + sign * left * c, 0, -1, false];
+                break;
+            case '=':
+                [b, c, sign, left, hasC] = [b + sign * left * c, 0, 1, -1, false];
+                break;
+            default:
+                [c, hasC] = [c * 10 + Number(z), true];
+                break;
+        }
+    }
+    b += sign * left * c;
+    if (a === 0 && b === 0) {
+        return "Infinite solutions";
+    } else if (a === 0) {
+        return "No solution";
+    } else {
+        return "x=" + -b / a;
+    }
+}
+
+console.assert(solveEquation("x+5-3+x=6+x-2") === "x=2");
+console.assert(solveEquation("x=x") === "Infinite solutions");
+console.assert(solveEquation("2x=x") === "x=0");
+console.assert(solveEquation("0x=0") === "Infinite solutions");
+console.assert(solveEquation("0=0x") === "Infinite solutions");

c_sharp/my_leetcode/Program.cs

@@ -1,2 +1,7 @@
 // See https://aka.ms/new-console-template for more information
+
+using my_leetcode;
+
 Console.WriteLine("Hello, World!");
+var s = new Solution();
+Console.WriteLine(s.SolveEquation("x+5-3+x=6+x-2"));//x=2

c_sharp/my_leetcode/Solution.cs

@@ -34,5 +34,34 @@ namespace my_leetcode
             f = f * 0.5 + xHalf / f;
             return (int)f;
         }
+
+        /// <summary>
+        /// 640. 求解方程
+        /// </summary>
+        /// <param name="equation">方程式</param>
+        /// <returns>解</returns>
+        public string SolveEquation(string equation)
+        {
+            var (a, b, c, sign, left, hasC) = (0, 0, 0, 1, 1, false);
+            foreach (var z in equation)
+            {
+                (a, b, c, sign, left, hasC) = z switch
+                {
+                    'x' => (a + (hasC ? sign * left * c : sign * left), b, 0, sign, left, false),
+                    '+' => (a, b + sign * left * c, 0, 1, left, false),
+                    '-' => (a, b + sign * left * c, 0, -1, left, false),
+                    '=' => (a, b + sign * left * c, 0, 1, -1, false),
+                    _ => (a, b, c * 10 + z - '0', sign, left, true)
+                };
+            }
+
+            b += sign * left * c;
+            return a switch
+            {
+                0 when b == 0 => "Infinite solutions",
+                0 => "No solution",
+                _ => "x=" + -b / a
+            };
+        }
     }
 }

cpp/src/Solution.h

@@ -11,6 +11,7 @@
 #include <functional>
 #include <semaphore.h>
 #include <queue>
+#include <stack>
 #include "structure.h"
 
 using namespace std;
@@ -131,6 +132,54 @@ public:
     static bool check(TreeNode *l, TreeNode *r) {
         return (!l && !r) || (l && r) && (l->val == r->val) && check(l->left, r->right) && check(l->right, r->left);
     }
+
+    bool isValid(const string& s) {
+        if (s.size() & 1) return false;
+        std::stack<char> stack;
+        for (char c: s)
+            if (c == '(' || c == '[' || c == '{') stack.push(c + (1 << (c & 1)));
+            else if (stack.empty() || stack.top() != c) return false;
+            else stack.pop();
+        return stack.empty();
+    }
+
+    /**
+     * 640. 求解方程
+     * @param equation 方程式
+     * @return 解
+     * @see <a href="https://leetcode-cn.com/problems/solve-the-equation/">原题链接</a>
+     */
+    string solveEquation(const string& equation) {
+        int a = 0, b = 0, c = 0, sign = 1, left = 1;
+        bool hasC = false;
+        for(char z : equation) {
+            switch (z) {
+                case 'x':
+                    a += hasC ? sign * left * c : sign * left, c = 0, hasC = false;
+                    break;
+                case '+':
+                    b += sign * left * c, c = 0, sign = 1, hasC = false;
+                    break;
+                case '-':
+                    b += sign * left * c, c = 0, sign = -1, hasC = false;
+                    break;
+                case '=':
+                    b += sign * left * c, c = 0, sign = 1, left = -1, hasC = false;
+                    break;
+                default:
+                    c = c * 10 + z - '0', hasC = true;
+                    break;
+            }
+        }
+        b += sign * left * c;
+        if (a == 0 && b == 0) {
+            return "Infinite solutions";
+        } else if (a == 0) {
+            return "No solution";
+        } else {
+            return "x=" + std::to_string(-b / a);
+        }
+    }
 };
 
 /**

java/src/com/iqiaoxu/code/Solution.java

@@ -84,4 +84,55 @@ public class Solution {
                isSymmetric(new TreeNode(0, root.left.left, root.right.right)) &&
                isSymmetric(new TreeNode(0, root.left.right, root.right.left));
     }
+
+    /**
+     * 640.求解方程
+     * @param equation 方程式
+     * @return 解
+     * @see <a href="https://leetcode-cn.com/problems/solve-the-equation/">原题链接</a>
+     */
+    public String solveEquation(String equation) {
+        int a = 0, b = 0, c = 0, sign = 1, left = 1;
+        boolean hasC = false;
+        for (byte z : equation.getBytes()) {
+            switch (z) {
+                case 'x':
+                    a += hasC ? sign * left * c : sign * left;
+                    c = 0;
+                    hasC = false;
+                    break;
+                case '+':
+                    b += sign * left * c;
+                    c = 0;
+                    sign = 1;
+                    hasC = false;
+                    break;
+                case '-':
+                    b += sign * left * c;
+                    c = 0;
+                    sign = -1;
+                    hasC = false;
+                    break;
+                case '=':
+                    b += sign * left * c;
+                    c = 0;
+                    sign = 1;
+                    left = -1;
+                    hasC = false;
+                    break;
+                default:
+                    c = c * 10 + z - '0';
+                    hasC = true;
+                    break;
+            }
+        }
+        b += sign * left * c;
+        if (a == 0 && b == 0) {
+            return "Infinite solutions";
+        } else if (a == 0) {
+            return "No solution";
+        } else {
+            return "x=" + -b / a;
+        }
+    }
 }

python/Solution.py

@@ -88,3 +88,23 @@ class Solution:
                not (root.left is None or root.right is None or root.left.val != root.right.val) and \
                self.isSymmetric(TreeNode(0, root.left.left, root.right.right)) and \
                self.isSymmetric(TreeNode(0, root.left.right, root.right.left))
+
+    def solveEquation(self, equation: str) -> str:
+        """
+        640. 求解方程
+        :param equation: 方程式
+        :return: 解
+        """
+        a, b, c, sign, left, has_c = 0, 0, 0, 1, 1, False
+        for z in equation:
+            match z:
+                case 'x': a, c, has_c = a + (sign * left * c if has_c else sign * left), 0, False
+                case '+': b, c, sign, has_c = b + sign * left * c, 0, 1, False
+                case '-': b, c, sign, has_c = b + sign * left * c, 0, -1, False
+                case '=': b, c, sign, left, has_c = b + sign * left * c, 0, 1, -1, False
+                case _: c, has_c = c * 10 + int(z), True
+        b += sign * left * c
+        match (a, b):
+            case (0, 0): return "Infinite solutions"
+            case (0, _): return "No solution"
+            case _: return f"x={-b // a}"

rust/src/implements/q0640.rs

@@ -30,7 +30,7 @@ impl Solution {
     ///     * 字符串
     ///     * 模拟
     pub fn solve_equation(equation: String) -> String {
-        let (mut a,mut b,mut c) = (0, 0, 0);
+        /*let (mut a,mut b,mut c) = (0, 0, 0);
         let mut sign = 1;
         let mut left = 1;
         let mut has_c = false;
@@ -71,6 +71,19 @@ impl Solution {
             (0, 0) => "Infinite solutions".to_owned(),
             (0, _) => "No solution".to_owned(),
             _ => format!("x={}", -b / a)
+        }*/
+        match equation.into_bytes().into_iter().fold((0, 0, 0, 1, 1, false), |(a, b, c, sign, left, has_c), z| match z {
+            b'x' => (a + if has_c { sign * left * c } else { sign * left }, b, 0, sign, left, false),
+            b'+' => (a, b + sign * left * c, 0, 1, left, false),
+            b'-' => (a, b + sign * left * c, 0, -1, left, false),
+            b'=' => (a, b + sign * left * c, 0, 1, -1, false),
+            _ => (a, b, c * 10 + (z - b'0') as i32, sign, left, true)
+        }) {
+            (a, b, c, sign, left, _) => match (a, b + sign * left * c) {
+                (0, 0) => "Infinite solutions".to_owned(),
+                (0, _) => "No solution".to_owned(),
+                (_, b) => format!("x={}", -b / a)
+            }
         }
     }
 }