HDU 1004(字典树，c++ map)

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题意：给出一个n与n个颜色，求出现次数最多的颜色。

暴力方法：

#include <stdio.h>#include <string.h>int main(){    int n,i,max=1,count=0,flag,j;        while(1)    {        char a[1000][50];        max=1;        scanf("%d",&n);        if(n==0)            break;                getchar();        for(i=0;i<n;i++)            gets(a[i]);        if(n==1)        {            puts(a[0]);            continue;        }        for(i=0;i<n;i++)        {            count=0;            for(j=0;j<n;j++)            {                if(strcmp(a[i],a[j])==0)                    count++;            }            if(count>max)            {                max=count;                flag=i;            }        }        puts(a[flag]);    }    return 0;}

c++ map的使用：

#include <cstdio>#include <map>#include <iostream>#include <string>using namespace std;void main(){    int N;    string ballon;    while (cin >> N, N)    {        map<string, int> m;        int n = N;        while (n--)        {            cin >> ballon;            ++m[ballon];        }        map<string, int>::iterator p;        int max = 0;        string max_ballon;        for (p = m.begin(); p != m.end(); ++p)        {            if (p->second > max)            {                max = p->second;                max_ballon = p->first;            }        }        cout << max_ballon << endl;    }}

字典树的使用：

#include <iostream>#include <cstring>#include <algorithm>#include <string>#include <cstdio>using namespace std;struct Trie{    int base;    Trie* next[26];    Trie() : base(-1) { memset(next, NULL, sizeof next); }};string color[1002];int _count[1002];int cnt;void insert(Trie* root, string& line){    Trie* p = root;    int len = line.length(), n;    for (int i = 0; i < len; ++i)    {        n = line[i] - 'a';        if (p->next[n] == NULL)            p->next[n] = new Trie;        p = p->next[n];    }    if (p->base == -1)    {        p->base = cnt;        color[cnt++] = line;    }    ++_count[p->base];}void freeTrie(Trie* root){    for (int i = 0; i < 26; ++i)        if (root->next[i])            freeTrie(root->next[i]);    delete root;}int main(){    int n, i;    string line;    Trie* root;    while (cin >> n && n)    {        root = new Trie;        cnt = 0;        memset(_count, 0, sizeof _count);        for (i = 0; i < n; ++i)        {            cin >> line;            insert(root, line);        }        int _max = 0, base;        for (i = 0; i < cnt; ++i)            if (_count[i] > _max)            {                _max = _count[i];                base = i;            }        cout << color[base] << endl;        freeTrie(root);    }}

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