CodeForces 828C String Reconstruction（并查集思想）

#include<stack>
#include<vector>
#include<queue>
#include<set>
#include<cstring>
#include<string>
#include<sstream>
#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#define ll long long
#define ull unsigned long long
using namespace std;
const int maxn = 1000000+5;
const int seed = 131;
const int MOD = 100013;
const int INF = 0x3f3f3f3f;
char ans[maxn*10];
int fa[maxn*10];
char s[maxn];
int find(int x){
    return fa[x] == x? x : fa[x] = find(fa[x]);
}
int main(){
    int n,t;
    memset(ans,0,sizeof(ans));
    scanf("%d",&n);
    for(int i = 0;i < maxn * 10;i++) fa[i] = i;
    int end = 1;
    while(n--){
        scanf("%s%d",s,&t);
        int len = strlen(s);
        while(t--){
            int x;
            scanf("%d",&x);
            end = max(end,x + len - 1);
            for(int i = find(x);i <= x + len -1;i = find(i + 1)){
                ans[i] = s[i - x];
                int fx = find(i);
                int fy = find(i + 1);
                if(fx > fy)
                    fa[fy] = fx;
                else
                    fa[fx] = fy;
            }
        }
    }
    for(int i = 1;i <= end;i++)
        if(ans[i] != 0)printf("%c",ans[i]);
        else printf("a");
    printf("\n");
    return 0;
}