UVA 11732 strcmp() Anyone?（左儿子右兄弟Trie）

ACM

题目地址： 
UVA 11732 strcmp() Anyone?

题意： 
问strcmp函数的==语句执行了几次。

分析： 
大白上的题目。 
听说要用左儿子右兄弟的Trie，比较省空间，顺便学了下。 
开始先建树记录次数，然后再遍历统计，结果错了... 
后面参考了Shoutmon巨巨的写法，一边insert一边统计。

代码：

/**  Author:      illuz <iilluzen[at]gmail.com>*  File:        uva11732.cpp*  Create Date: 2014-09-24 10:30:15*  Descripton:  trie son brother*/#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;#define repf(i,a,b) for(int i=(a);i<=(b);i++)typedef long long ll;const int N = 0;const int MAXNODE =4000010;int n, cas;ll ans;char str[4001];struct STrie {int son[MAXNODE];int bro[MAXNODE];int val[MAXNODE];char ch[MAXNODE];int sz;STrie() { sz = 1; ch[0] = val[0] = bro[0] = son[0] = 0; }void init() { sz = 1; ch[0] = val[0] = bro[0] = son[0] = 0; }// inline int idx(char c) { return c - 'a'; }void insert(char *s) {int len = strlen(s), u = 0, p;repf (i, 0, len) {// check the brother of ufor (p = son[u]; p; p = bro[p]) {if (ch[p] == s[i])break;}// cannot find out than insertif (!p) {p = sz++;ch[p] = s[i];bro[p] = son[u];son[p] = 0;val[p] = 0;son[u] = p;}ans += (val[u] - val[p]) * (2 * i + 1);if (len == i) {ans += val[p] * (2 * i + 2);val[p]++;}val[u]++;u = p;}}} trie;int main() {// ios_base::sync_with_stdio(0);while (~scanf("%d", &n) && n) {trie.init();ans = 0;repf (i, 0, n - 1) {scanf("%s", str);trie.insert(str);}printf("Case %d: %lld\n", ++cas, ans);}return 0;}