hdu6375 度度熊学队列

度度熊学队列

题目传送门

解题思路

STL大法好。直接用deque，但是N的范围很大，如果直接开那么多的deque会爆内存，所以用map< int, deque< int>>，多组数据，记得清空map。

代码如下

#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
using namespace std;
typedef long long ll;

inline int read(){
    int res = 0, w = 0; char ch = 0;
    while(!isdigit(ch)){
        w |= ch == '-', ch = getchar();
    }
    while(isdigit(ch)){
        res = (res << 3) + (res << 1) + (ch ^ 48);
        ch = getchar();
    }
    return w ? -res : res;
}

const int N = 100005;

map<int, deque<int>> mp;
int main()
{
    int n, q;
    while(scanf("%d%d", &n, &q)!= EOF){
        for(int i = 1; i <= n; i ++)
            mp[i].clear();
        for(int i = 1; i <= q; i ++){
            int opt;
            opt = read();
            if(opt == 1){
                int u, w, val;
                u = read(), w = read(), val = read();
                if(w)
                    mp[u].push_back(val);
                else
                    mp[u].push_front(val);
            }
            else if(opt == 2){
                int u, w;
                u = read(), w = read();
                if(!mp[u].empty()){
                    if(w){
                        printf("%d\n", mp[u].back());
                        mp[u].pop_back();
                    }
                    else{
                        printf("%d\n", mp[u].front());
                        mp[u].pop_front();
                    }
                }
                else
                    printf("-1\n");
            }
            else {
                int u, v, w;
                u = read(), v = read(), w = read();
                if(w)
                    mp[u].insert(mp[u].end(), mp[v].rbegin(), mp[v].rend());
                else
                    mp[u].insert(mp[u].end(), mp[v].begin(), mp[v].end());
                mp[v].clear();
            }
        }
    }
    return 0;