洛谷 P1873 砍树

最新推荐文章于 2024-01-05 13:08:31 发布

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最新推荐文章于 2024-01-05 13:08:31 发布 · 689 阅读

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#c++ #算法 #二分答案 #二分法

这篇博客介绍了如何利用二分答案的策略解决洛谷P1873砍树问题，实现了在300毫秒内的高效解法。

P1873 砍树

二分答案（300+ms）

#include <cstdio>
#include <algorithm>
#define MAXN 1000100
#define LL long long
#define RE register
using namespace std;
LL a[MAXN];
inline LL read() {
	LL x = 0;
	char c = getchar();
	while (c < '0' || c > '9') {
		c = getchar();
	}
	while ('0' <= c && c <= '9') {
		x = (x << 3) + (x << 1) + (c ^ 0x30);
		c = getchar();
	}
	return x;
}
int main() {
	LL N = read();
	LL M = read();
	LL right = 0;
	for (RE LL i = 0; i < N; ++i) {
		a[i] = read();
		right = a[i] > right ? a[i] : right;
	}
	LL left = 0;
	while (left <= right) {
		LL mid = (left + right) >> 1;
		LL tmp = 0;
		for (RE LL i = 0; i < N; ++i) {
			if (a[i] > mid) {
				tmp += a[i] - mid;
			}
		}
		i