Poj 2018 Best Cow Fences
实数二分+前缀和维护
调了一晚上， 但发现没什么注意事项orz
无输出只因eps定义成了int型QAQ哭唧唧
#include<cstdio> #include<iostream> using namespace std; const int sz = 100010; double eps = 1e-5; int n, f; double a[sz], b[sz], sum[sz]; bool check(double k) {double minn = 1e10, ans = -1e10;for(int i = 1; i <= n; i++)b[i] = a[i] - k;for(int i = 1; i <= n; i++)sum[i] = sum[i-1] + b[i];for(int i = f; i <= n; i++) {minn = min(minn, sum[i - f]);ans = max(ans, sum[i] - minn);}if(ans >= 0) return true;else return false; } int main() {scanf("%d%d", &n, &f); for(int i = 1; i <= n; i++)scanf("%lf", &a[i]);double l = -1e6, r = 1e6, ans = 0;while(r - l > eps) {double mid = (l + r) / 2.0;if(check(mid)) l = mid;else r = mid;}cout<< int(r * 1000) <<endl;return 0; }
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