PAT(甲级)渡劫(二十一)-Set Similarity(25)

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PAT(甲级)渡劫(二十一)-Set Similarity(25)

代码如下：

#include <iostream>
#include <cstdio>
#include <set>
#include <vector>

using namespace std;

vector<set<int> > v;    // 集合数组

double Similarity(set<int> &a,set<int> &b){
    set<int>::iterator x = a.begin();
    set<int>::iterator y = b.begin();
    int samecnt = 0;
    while(x != a.end() && y != b.end()){
        if(*x == *y){
            samecnt++;
            ++x;
            ++y;
        }else if(*x < *y) ++x;
        else ++y;
    }
    double ret = 1.0*samecnt/(a.size()+b.size()-samecnt);
    return ret;
}

int main(){
    freopen("in.txt","r",stdin);
    int n,q;
    scanf("%d",&n);
    v.resize(n+1);
    for(int i = 1 ; i <= n ; i++){
        int m;
        scanf("%d",&m);
        while(m--){
            int x;
            scanf("%d",&x);
            v[i].insert(x);
        }
    }
    scanf("%d",&q);
    while(q--){
        int x,y;
        scanf("%d%d",&x,&y);
        double ret = Similarity(v[x],v[y])*100;
        printf("%.1lf%%\n",ret);
    }

    return 0;
}

运行结果：