《贪心+优先队列(哈夫曼思想)poj-3253-fence-repair》由会员分享，可在线阅读，更多相关《贪心+优先队列(哈夫曼思想)poj-3253-fence-repair（3页珍藏版）》请在金锄头文库上搜索。
1、Fence RepairTime Limit: 2000MSMemory Limit: 65536KTotal Submissions: 33173Accepted: 10714DescriptionFarmer John wants to repair a small length of the fence around the pasture. He measures the fence and finds that he needs N (1 N 20,000) planks of wood, each having some integer length Li (1 Li 50,000
2、) units. He then purchases a single long board just long enough to saw into the N planks (i.e., whose length is the sum of the lengths Li). FJ is ignoring the kerf, the extra length lost to sawdust when a sawcut is made; you should ignore it, too.FJ sadly realizes that he doesnt own a saw with which
3、 to cut the wood, so he mosies over to Farmer Dons Farm with this long board and politely asks if he may borrow a saw.Farmer Don, a closet capitalist, doesnt lend FJ a saw but instead offers to charge Farmer John for each of the N-1 cuts in the plank. The charge to cut a piece of wood is exactly equ
4、al to its length. Cutting a plank of length 21 costs 21 cents.Farmer Don then lets Farmer John decide the order and locations to cut the plank. Help Farmer John determine the minimum amount of money he can spend to create the N planks. FJ knows that he can cut the board in various different orders w
5、hich will result in different charges since the resulting intermediate planks are of different lengths.InputLine 1: One integer N, the number of planks Lines 2.N+1: Each line contains a single integer describing the length of a needed plankOutputLine 1: One integer: the minimum amount of money he mu
6、st spend to make N-1 cutsSample Input3858Sample Output34HintHe wants to cut a board of length 21 into pieces of lengths 8, 5, and 8. The original board measures 8+5+8=21. The first cut will cost 21, and should be used to cut the board into pieces measuring 13 and 8. The second cut will cost 13, and
7、should be used to cut the 13 into 8 and 5. This would cost 21+13=34. If the 21 was cut into 16 and 5 instead, the second cut would cost 16 for a total of 37 (which is more than 34).SourceUSACO 2006 November Gold有一个农夫要把一个木板钜成几块给定长度的小木板，每次锯都要收取一定费用，这个费用就是当前锯下的这个木版的长度。给定各个要求的小木板的长度，及小木板的个数n，求最小费用。可以看成是
8、把n段木板拼成一块，每次拼的代价为所拼木板的长度和。这就跟哈夫曼编码一样，每次选取两个最小的来拼。具体实现时用优先队列。/876K47MS#include #include #includeusing namespace std;#define INF 0x7fffffffpriority_queueint,vector,greater pq;int main() freopen(input.txt,r,stdin); freopen(output.txt,w,stdout); int n,i,l,a,b; long long ans; while(scanf(%d,&n)!=EOF) for(i=0;in;i+) scanf(%d,&l); pq.push(l); pq.push(INF); ans=0; while(!pq.empty() a=pq.top(),pq.pop(); b=pq.top(),pq.pop(); if(b=INF) break; ans+=(a+b); /cout a b ansendl; pq.push(a+b);printf(%lldn,ans); return 0;
