愤怒的牛

题目描述

思路

思路

#include <cstdio>

const int inf = 0x3f3f3f3f;
int n, m, ans, L = inf, R = 0, arr[100005];
inline int read() {
	int s = 0, f = 1;
	char ch = getchar();
	while (ch < '0' || ch > '9') {
		if (ch == '-') f = -1;
		ch = getchar();
	}
	while (ch >= '0' && ch <= '9') s = s * 10 + ch - '0', ch = getchar();
	return s * f;
}
void qsort(int L, int R) {
	int l = L, r = R;
	int mid = arr[l + r >> 1], tmp;
	while (l < r) {
		while (arr[l] < mid) l++;
		while (arr[r] > mid) r--;
		if (l <= r) {
			tmp = arr[l];
			arr[l] = arr[r];
			arr[r] = tmp;
			l++, r--;
		}
	}
	if (L < r) qsort(L, r);
	if (l < R) qsort(l, R);
}

int main() {
	n = read(), m = read();
	for (int i = 1; i <= n; ++i) arr[i] = read();
	qsort(1, n);
	int l = 1, r = arr[n];
	while (l <= r) {
		int mid = l + r >> 1, cnt = 0, pre;
		for (int i = 1; i <= n; ++i) {
			if (i == 1) {
				cnt = 1; pre = arr[1];
			} else if (arr[i] - pre >= mid){
				pre = arr[i], cnt++;
			}
		}
		if (cnt >= m) {
			ans = mid; l = mid + 1;
		} else r = mid - 1;
	}
	printf("%d
", ans);
	return 0;
}