Connections in Galaxy War(反向并查集)

题目链接上一种法:http://blog.csdn.net/qq_37753409/article/details/77922448.
提交后发现Runtime error. 查阅资料后,发现要是用反向并查集,在这里用反向并查集实现.
题目链接:https://vjudge.net/problem/ZOJ-3261
代码如下:

#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#include <set>using namespace std;const int STAR_SIZE = 10010;const int INQUIRY_SIZE = 50010;struct Star{    int ID;    int POWER;    void setData(int id, int power){        ID = id;        POWER = power;    }};struct Inquiry{    int a, b;    int flag;    int ans;    void setData(int f, int aa, int bb){        a = aa;        b = bb;        flag = f;    }};Star star[STAR_SIZE];Inquiry inquiry[INQUIRY_SIZE];int MAX[STAR_SIZE];set< pair<int, int> > T;void init(){    T.clear();    for(int i = 0; i < STAR_SIZE; ++i){        star[i].setData(i, -1);    }    for(int i = 0; i < INQUIRY_SIZE; ++i){        inquiry[i].setData(-1, 0, 0);        inquiry[i].ans = -1;    }    memset(MAX, -1, sizeof(MAX));} int find(int p){    if(star[p].ID != p){        int d = star[p].ID;        star[p].ID = find(star[p].ID);        MAX[p] = max(MAX[p], MAX[d]);    }    return star[p].ID;}void Union(int a, int b){    int x = find(a);    int y = find(b);    if(x == y) return;    if(MAX[x] < MAX[y] || (MAX[x] == MAX[y] && x > y)){        star[x].ID = y;    }else{        star[y].ID = x;    }   }int main(){    int n, m, q;    int k = 0;    while(~scanf("%d", &n)){        if(k++)puts("");        init();        char op[10];        int a, b;        for(int i = 0; i < n; ++i){            scanf("%d", &star[i].POWER);        }        scanf("%d", &m);        for(int i = 0; i < m; ++i){            scanf("%d%d", &a, &b);            if(a > b) swap(a, b);                       T.insert(make_pair(a, b));        }        scanf("%d", &q);        for(int i = 0; i < q; ++i){            scanf("%s", op);            if(op[0] == 'q'){                scanf("%d", &a);                inquiry[i].setData(0, a, 0);            }else if(op[0] == 'd'){                scanf("%d%d", &a, &b);                if(a > b) swap(a, b);                T.erase(make_pair(a, b));                inquiry[i].setData(1, a, b);            }        }        for(int i = 0; i < n; ++i){            MAX[i] = star[i].POWER;        }        for(set< pair<int, int> >::iterator it = T.begin(); it != T.end(); it++){            a = (*it).first;            b = (*it).second;            Union(a, b);        }        for(int i = q - 1; i >= 0; i--){            if(inquiry[i].flag == 0){                if(MAX[find(inquiry[i].a)] > star[inquiry[i].a].POWER){                    inquiry[i].ans = star[inquiry[i].a].ID;                }else{                    inquiry[i].ans = -1;                }            }else if(inquiry[i].flag == 1){                Union(inquiry[i].a, inquiry[i].b);            }        }        for(int i = 0;i < q; i++)        {            if(inquiry[i].flag == 0)            {                printf("%d\n",inquiry[i].ans);            }                       }    }    return 0;}