#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>using namespace std;#define maxn 100005#define maxk 32int sum[maxn][maxk], c[maxn][maxk];int head[maxn], next[maxn], v[maxn], ecount;int n, p;void addedge(int a, int b){ next[ecount] = head[a]; head[a] = ecount; v[ecount] = b; ecount++;}int hash(int c[]){ int ret =0; for (int i =0; i < p; i++) ret = ((ret <<2) + (c[i] >>4)) ^ (c[i] <<10); ret = (ret % maxn + maxn) % maxn; return ret;}void input(){ memset(sum, 0, sizeof(sum)); memset(c, 0, sizeof(c)); memset(head, -1, sizeof(head)); scanf("%d%d", &n, &p); ecount =0; int ans =0; addedge(hash(c[0]), 0); for (int i =1; i <= n; i++) { int a; scanf("%d", &a); for (int j =0; j < p; j++) { sum[i][j] = sum[i -1][j] + (1& a); a >>=1; } for (int j =0; j < p; j++) c[i][j] = sum[i][j] - sum[i][0]; int h = hash(c[i]); for (int j = head[h]; j !=-1; j = next[j]) { int ok =true; for (int k =0; k < p; k++) if (c[v[j]][k] != c[i][k]) { ok =false; break; } if (ok && ans < i - v[j]) ans = i - v[j]; } addedge(h, i); } printf("%dn", ans);}int main(){ input(); return 0;}
