题目链接： http://poj.org/problem?id=3274
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 bool feature[100001][30]; 6 int sum[100001][30], c[100001][30], n, k; 7 const int prime = 99991; 8 9 struct hash_table 10 { 11 int flag; 12 struct hash_table *next; 13 }*Hash[prime]; 14 15 int hash_insert(int key, int flag) 16 { 17 if(Hash[key] == NULL) 18 { 19 Hash[key] = new hash_table; 20 Hash[key]->flag = flag; 21 Hash[key]->next = NULL; 22 return 0; 23 } 24 struct hash_table *p = Hash[key]; 25 while(p->next != NULL) 26 { 27 bool ok = 1; 28 for(int i = 0; i < k; i++) 29 { 30 if(c[p->flag][i] != c[flag][i]) 31 { 32 ok = 0; 33 break; 34 } 35 } 36 if(ok)return flag - p->flag; 37 p = p->next; 38 } 39 for(int i = 0; i < k; i++) 40 { 41 if(c[p->flag][i] != c[flag][i]) 42 { 43 p->next = new hash_table; 44 p->next->flag = flag; 45 p->next->next = NULL; 46 return 0; 47 } 48 } 49 return flag - p->flag; 50 } 51 52 int main() 53 { 54 int x; 55 while(scanf("%d %d", &n, &k) != EOF) 56 { 57 memset(Hash, 0, sizeof(Hash)); 58 for(int i = 1; i <= n; i++) 59 { 60 scanf("%d", &x); 61 for(int j = 0; j < k; j++) 62 feature[i][j] = (x >> j) & 1; 63 } 64 memset(sum[0], 0, sizeof(sum[0])); 65 memset(feature[0], 0, sizeof(feature[0])); 66 int ans = 0; 67 hash_insert(0, 0); 68 for(int i = 1; i <= n; i++) 69 { 70 int key = 0; 71 for(int j = 0; j < k; j++) 72 { 73 sum[i][j] = sum[i-1][j] + feature[i][j]; 74 c[i][j] = sum[i][j] - sum[i][0]; 75 key += c[i][j] * j; 76 } 77 ans = std::max(ans, hash_insert(std::abs(key)%prime, i)); 78 } 79 printf("%d ", ans); 80 } 81 return 0; 82 }