zoukankan      html  css  js  c++  java
  • Trie UVA 11732 "strcmp()" Anyone?

    题目传送门

    题意:询问所有字符串的比较次数和(注意for循环内的比较也算)

    分析:将所有字符串插入到字典树上,然后结点信息记录有几个字符串,那么每走到一个结点就能知道比较到此时需要的次数。学习到链表存结点

    #include <bits/stdc++.h>
    using namespace std;
    
    typedef long long ll;
    const int N = 4e3 + 5;
    const int M = 1e3 + 5;
    const int NODE = N * M;
    struct Trie	{
    	int head[NODE], nex[NODE];
    	char ch[NODE];
    	int cnt[NODE];
    	int sz;
    	void clear()	{
    		sz = 1;	cnt[0] = head[0] = nex[0] = 0;
    	}
    	void insert(char *str)	{
    		int u = 0, len = strlen (str);
    		cnt[0]++;
    		for (int i=0; i<=len; ++i)	{
    			bool found = false;
    			int v;
    			for (v=head[u]; v; v=nex[v])	{
    				if (ch[v] == str[i])	{
    					found = true;	break;
    				}
    			}
    			if (!found)	{       //插入到链表的头结点后一个
    				v = sz++;
    				cnt[v] = 0;
    				ch[v] = str[i];
    				nex[v] = head[u];
    				head[u] = v;
    				head[v] = 0;
    			}
    			u = v;	cnt[u]++;
    		}
    	}
    	void query(int u, int dep, ll &res)	{
    		if (!head[u])	{
    			res += cnt[u] * (cnt[u] - 1) * dep;
                return ;
    		}
    		int sum = 0, tmp = cnt[u];
    		for (int v=head[u]; v; v=nex[v])	{
    		    //sum += cnt[v] * (cnt[u] - cnt[v]);
                res += cnt[v] * (tmp - cnt[v]) * (dep * 2 + 1);
    			tmp -= cnt[v];
            }
            //res += sum / 2 * (2 * dep + 1);
    		for (int v=head[u]; v; v=nex[v])	{
    			query (v, dep + 1, res);
    		} 
    	}
    }trie;
    char word[M];
    
    int main(void)	{
    	int n, cas = 0;
    	while (scanf ("%d", &n) == 1)	{
    		if (!n)	break;
    		trie.clear ();
    		for (int i=0; i<n; ++i)	{
    			scanf ("%s", &word);
    			trie.insert (word);
    		}
    		ll ans = 0;
    		trie.query (0, 0, ans);
    		printf ("Case %d: %lld
    ", ++cas, ans);
    	}
    
    	return 0;
    }
    

      

    编译人生,运行世界!
  • 相关阅读:
    Palindrome Linked List 解答
    Word Break II 解答
    Array vs Linked List
    Reverse Linked List II 解答
    Calculate Number Of Islands And Lakes 解答
    Sqrt(x) 解答
    Find Median from Data Stream 解答
    Majority Element II 解答
    Binary Search Tree DFS Template
    188. Best Time to Buy and Sell Stock IV
  • 原文地址:https://www.cnblogs.com/Running-Time/p/5059642.html
Copyright © 2011-2022 走看看