度度熊学队列
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;