UVa 10391 - Compound Words

hash存储，遍历每个单词的所有拆分，看是否都存在。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <stack>
#include <queue>
#include <iostream>
#include <algorithm>

using namespace std;

#define MAXN 120100
#define INF 1e8
#define NEGINF -1e8

const int HASHSIZE = 121000;
int head[HASHSIZE], next[MAXN];

char str[MAXN][100];
int cnt[MAXN];

int hash(char s[])
{
unsigned int seed = 131;
unsigned int hash = 0;

int i;
int len = strlen(s);
for( i = 0; i < len; i++ )
hash = hash * seed + s[i];
return (hash & 0x7FFFFFFF) % HASHSIZE;
}

void add_hash(int s) {
int h = hash(str[s]);
next[s] = head[h];
head[h] = s;
}

int search(char *p) {
int h = hash(p);
int u = head[h];
while(u) {
if( !strcmp(str[u],p) ) return u;
u = next[u];
}
return -1;
}

int main() {
#ifndef ONLINE_JUDGE
freopen("data.in","r",stdin);
//freopen("data.out","w",stdout);
#endif

memset(head,0,sizeof(head));
memset(next,0,sizeof(next));
memset(cnt,0,sizeof(cnt));
int ix = 1;
int len;
while( gets(str[ix]) != NULL ) { /*hash*/
len = strlen(str[ix]);
cnt[len] = 1;
add_hash(ix);
ix++;
}

int i,j,k;

char s1[1000],s2[1000];
for( i = 1; i < ix; i++ ) {
len = strlen(str[i]);

for( j = 0; j < len - 1; j++ ) { /*遍历所有子拆分*/
int v1 = 0,v2 = 0;
for( k = 0; k <= j; k++ )
s1[v1++] = str[i][k];
s1[v1] = '\0';
for( k = j+1; k < len; k++ )
s2[v2++] = str[i][k];
s2[v2] = '\0';
if( cnt[v1] && cnt[v2] ) { /* 如果无此长度则不用搜索,优化后没多少效果。。*/
if( search(s1) != -1 && search(s2) != -1 ) {
printf("%s\n",str[i]);
break;
}
}
}
}

return 0;
}