Educational Codeforces Round 6 C. Pearls in a Row

题意：

找到最大连续有重复数字的子段

#include <iostream>#include <stdio.h>#include <map>#include <cstring>#include <queue>using namespace std;const int maxn=300005;int a[maxn];int l[maxn];int r[maxn];int now[maxn];int main(){    map<int,int>mp;    int n;    int cnt=0;    scanf("%d",&n);    for(int i=1;i<=n;i++)    {         scanf("%d",&a[i]);         if(mp.count(a[i])==0)         {             mp[a[i]]=++cnt;         }    }    int ans=0;    queue<int>q;    int st=1;    for(int i=1;i<=n;i++)    {        int pos=mp[a[i]];        if(now[pos]==0)        {            now[pos]=i;            q.push(pos);        }        else        {            l[++ans]=st;            r[ans]=i;            st=i+1;            while(!q.empty())            {                int t=q.front();                now[t]=0;                q.pop();            }        }    }    if(ans==0)    {        printf("-1\n");        return 0;    }    r[ans]=n;    printf("%d\n",ans);    for(int i=1;i<=ans;i++)    {        printf("%d %d\n",l[i],r[i]);    }    return 0;}