set的重载.

#include <bits/stdc++.h>using namespace std;struct point {   int x,y;   point(int xx = 0,int yy = 0):x(xx),y(yy) {}};struct cmp1 {    bool operator ()(pair<int,int>p1,pair<int,int>p2){        return p1.first == p2.first ?  p1.second < p2.second : p1.first < p2.first;    }};struct cmp2 {    bool operator () (point a,point b)  {        return a.x == b.x ? a.y < b.y : a.x < b.x ;    }};int main(){    /*    set<pair<int,int>,cmp1>pq;    set<point,cmp2>pq2;    pq2.insert(point(1,2));    pq2.insert(point(1,3));    cout << pq2.size() << endl;    pq.insert(make_pair(1,2));    pq.insert(make_pair(1,3));    cout << pq.size() << endl;    */    typedef pair<int,int> P;    P a(1,1),b(2,2);    P k = min(a,b);    cout << k.first << " " << k.second << endl;}