46 lines
895 B
C
46 lines
895 B
C
//
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// Created by Huang on 2021/11/9.
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//
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#include <stdio.h>
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/**
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* 69.Sqrt(x)
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* @param x x
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* @return 平方根
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*/
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int mySqrt(int x) {
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union {
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long long i;
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double f;
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}u;
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double xHalf = 0.5 * x;
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u.f = x;
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u.i = 0x1FF7A3BEA91D9B1B + (u.i >> 1);
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u.f = u.f * 0.5 + xHalf / u.f;
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u.f = u.f * 0.5 + xHalf / u.f;
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u.f = u.f * 0.5 + xHalf / u.f;
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return u.f;
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}
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/**
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* 69.Sqrt(x)
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* @param x x
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* @return 平方根
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*/
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int mySqrt1(int x) {
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double xHalf = 0.5 * x;
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double f = x;
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long long i = *(long long *) &f;
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i = 0x1FF7A3BEA91D9B1B + (i >> 1);
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f = *(double *) &i;
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f = f * 0.5 + xHalf / f; // 牛顿迭代法，重复此句可提高精度
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f = f * 0.5 + xHalf / f;
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f = f * 0.5 + xHalf / f; // 三次迭代
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return f;
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}
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int main() {
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printf("Hello, World!\n");
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printf("%d", mySqrt1(2147395599));
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return 0;
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} |