hdu 3530 单调队列优化DP

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AC代码如下：

#include <iostream>#include <cstring>#include <cstdio>#include <algorithm>using namespace std;int q1[211000], pos1[211000], head1, tail1;int q2[211000], pos2[211000], head2, tail2;int ans, now;int N, M, K;int num[211000];int main(){    while( scanf( "%d%d%d", &N, &M, &K ) != EOF ){        for( int i = 1; i <= N; i++ ){            scanf( "%d", &num[i] );        }        head1 = head2 = 0;        tail1 = tail2 = -1;        ans = 0;        now = 0;        for( int i = 1; i <= N; i++ ){            now++;            while( head1 <= tail1 && num[i] > q1[tail1] )    tail1--;            q1[++tail1] = num[i];pos1[tail1] = i;            while( head2 <= tail2 && num[i] < q2[tail2] )    tail2--;            q2[++tail2] = num[i];pos2[tail2] = i;            while( q1[head1] - q2[head2] > K ){                if( pos1[head1] < pos2[head2] ){                    now = i - pos1[head1];                    head1++;                }else{                    now = i - pos2[head2];                    head2++;                }            }            if( q1[head1] - q2[head2] >= M ){                ans = max( ans, now );            }        }        cout << ans << endl;    }    return 0;}

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