牛客oj 習題10.2 查找第K小數（set）&& 習題10.3 搬水果（哈夫曼樹）

 

本來以爲用set做就夠煩了，後來想想最簡的打表也並不清爽，心裏有點平衡。。

 

 

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <set>
#include <queue>
#include <cmath>
#include <climits>
 
using namespace std;
 
const int MAXN = 1005;
const int INF = INT_MAX;

int main(){
//	freopen("in.txt", "r", stdin);
	int n, k, x;
	while(~scanf("%d", &n)){
		set<int> myset;
		for(int i = 0; i < n; i++){
			scanf("%d", &x);
			myset.insert(x);
		}
		scanf("%d", &k);
		set<int>::iterator it;
		int time = 1;
		for(it = myset.begin(); it != myset.end(); it++){
			if(time == k){
				cout << *it << endl;
				break;
			}
			time ++;
		}
	}
	return 0;
}

 

 

哈夫曼樹水題，順便複習優先隊列，不過要記住輸出的是最大權值和而非頂點值！

 

 

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <cmath>
#include <climits>
 
using namespace std;
 
const int MAXN = 1005;
const int INF = INT_MAX;

int main(){
//	freopen("in.txt", "r", stdin);
	int n, x;
	while(~scanf("%d", &n)){
		if(n == 0) break;
		priority_queue<int, vector<int>, greater<int> > myqueue;
		for(int i = 0; i < n; i++){
			scanf("%d", &x);
			myqueue.push(x);
		}
		int ans = 0;
		while(myqueue.size() > 1){
			int x1 = myqueue.top();
			myqueue.pop();
			int x2 = myqueue.top();
			myqueue.pop();
			ans += (x1 + x2);
			myqueue.push(x1 + x2);
		}
		printf("%d\n", ans);
	}
	return 0;
}