1.题目:
2.解析:
代码:
public int mySqrt(int x) {
if(x < 1) return 0;
long left = 1,right = x;
while(left < right){
long mid =left + (right-left+1) / 2;
if(mid*mid <= x) left = mid;
else right = mid-1;
}
return (int)left;
}