贪心策略：一个直径为X的头颅，应该让雇佣费用满足大于等于X且最小的骑士来砍掉，这样才能使得花费最少。
AC代码
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <utility>
#include <string>
#include <iostream>
#include <map>
#include <set>
#include <vector>
#include <queue>
#include <stack>
using namespace std;
#pragma comment(linker, "/STACK:1024000000,1024000000")
#define eps 1e-10
#define inf 0x3f3f3f3f
#define PI pair<int, int>
typedef long long LL;
const int maxn = 2e4 + 5;
int head[maxn], kill[maxn];
int main() {
int n, m;
while(scanf("%d%d", &n, &m) == 2 && n && m) {
for(int i = 0; i < n; ++i) scanf("%d", &head[i]);
for(int i = 0; i < m; ++i) scanf("%d", &kill[i]);
sort(head, head + n);
sort(kill, kill + m);
int cnt = 0, cost = 0;
for(int i = 0; i < m; ++i) {
if(kill[i] >= head[cnt]) {
++cnt;
cost += kill[i];
if(cnt >= n) break;
}
}
if(cnt < n) printf("Loowater is doomed!\n");
else printf("%d\n", cost);
}
return 0;
}
如有不当之处欢迎指出！