SPOJ ADALIST Ada and List(vector的使用)

vector的使用会使代码变得很简单

#include<iostream>
#include<cstdio>
#include<vector>
using namespace std;
vector <int>a;
vector<int>::iterator it;

int main(){
int n , q, cmd, k, num;
while(scanf("%d%d", &n,&q) != EOF){
a.clear();
a.push_back(0);
while(n--){
scanf("%d", &num);
a.push_back(num);
}
while(q--){
scanf("%d%d", &cmd, &k);
if(cmd == 1){
scanf("%d", &num);
a.insert(a.begin() + k, num);
}
else if(cmd == 2){
a.erase(a.begin() + k);
}
else if(cmd == 3){
it = a.begin() + k;
printf("%d\n", *it);
}
}
}

return 0;
}