整数二分
int l = 0, r = n;
while (l <= r) {
int nMid = (l + r) >> 1;
if (Judge(x, y, nMid)) {
l = nMid + 1;
}
else {
r = nMid - 1;
}
}
//注意当l为0时, 输出0, 而非-1
cout << l - 1 << endl;
实数二分
double l = 0, r = n;
//精度具体看题意
while (r - l > 0.0001) {
double nMid = (l + r) / 2.0;
if (Judge(x, y, nMid)) {
l = nMid;
}
else {
r = nMid;
}
}
cout << l << endl;