实验三——贪心算法·哈夫曼编码

/*Hatsune Miku 4ever!*/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define _for(i,a,b) for(int i = (a);i < b;i ++)
#define _rep(i,a,b) for(int i = (a);i > b;i --)
#define INF 0x3f3f3f3f3f3f3f3f
#define lowbit(x) ((x)&(-x))
#define pb push_back
#define MIKU 39
#define Design ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define debug() printf("Miku Check OK!\n")
#define bigmiku 3939393939
#define maxn 100039
#define maxe 1000003

struct p
{
    int val;
    vector<char> nd;
    bool operator < (p b) const
    {
        return val > b.val;
    }
};
int n;
char s[30];
string rnt[30];
int a[30];
priority_queue<p> pq;
int main()
{
    printf("输入小写字母总数：");
    scanf("%d",&n);
    printf("输入小写字母和频率：\n");
    _for(i,1,n+1)
        scanf(" %c%d",&s[i],&a[i]);
    _for(i,1,n+1)
        pq.push({a[i],vector<char>(1,s[i])});
    
    while(pq.size()!=1)
    {
        p a1 = pq.top();
        pq.pop();
        p a2 = pq.top();
        pq.pop();
        p a3;
        a3.val = a1.val + a2.val;
        _for(i,0,a1.nd.size())
        {
            rnt[a1.nd[i]-‘a‘] += ‘1‘;
            a3.nd.pb(a1.nd[i]);
        }
        _for(i,0,a2.nd.size())
        {
            rnt[a2.nd[i]-‘a‘] += ‘0‘;
            a3.nd.pb(a2.nd[i]);
        }
        pq.push(a3);
    }
    _for(i,0,30)
        reverse(rnt[i].begin(),rnt[i].end());
    
//    _for(i,0,30)
//    while(rnt[i].size() && rnt[i][rnt[i].size()-1]==‘0‘)
//        rnt[i].pop_back();
    printf("小写字母及其对应哈夫曼编码：\n");
    _for(i,0,30)
        if(rnt[i].size())
            printf("%c %s\n",‘a‘+i,rnt[i].c_str());
    return 0;
}