BZOJ1691 [Usaco2007 Dec]挑剔的美食家

原来usaco的金组题这么难。。。蒟蒻根本不会T T

我只会贪心部分，然后发现要平衡树，就不行了。。。（论线段树都写不出的蒟蒻）

然后发现iwtwiioi的blog，Orz！原来可以用STL来做的说。。。

STL大法好！

/**************************************************************
    Problem: 1691
    User: rausen
    Language: C++
    Result: Accepted
    Time:336 ms
    Memory:3428 kb
****************************************************************/
 
#include <cstdio>
#include <algorithm>
#include <set>
 
using namespace std;
typedef long long ll;
const int N = 100005;
 
struct data{
    int x, y;
}a[N], b[N];
inline bool operator < (const data &a, const data &b){
    return a.y > b.y;
}
multiset <int> s;
multiset <int> :: iterator it;
int n, m, i, j = 1, x;
char ch;
ll ans;
 
inline unsigned int read(){
    x = 0;
    ch = getchar();
    while (ch < '0' || ch > '9')
        ch = getchar();
 
    while (ch >= '0' && ch <= '9'){
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x;
}
 
int main(){
    n = read(), m = read();
    for (i = 1; i <= n; ++i)
        a[i].x = read(), a[i].y = read();
    for (i = 1; i <= m; ++i)
        b[i].x = read(), b[i].y = read();
    sort(a + 1, a + n + 1);
    sort(b + 1, b + m + 1);
    for (i = 1; i <= n; ++i){
        while (a[i].y <= b[j].y && j <= m)
            s.insert(b[j].x), ++j;
        it = s.lower_bound(a[i].x);
        if (it == s.end()){
            printf("-1
");
            return 0;
        }
        ans += *it;
        s.erase(it);
    }
    printf("%lld
", ans);
    return 0;
}

（p.s. 蒟蒻被rank1.的iwtwiioi大神稳稳地踩在了脚下）