[UVA][DP] 10271 - Chopsticks
Problem C
Chopsticks
Input: Standard Input
Output: Standard Output
In China, people use a pair of chopsticks to get food on the table, but Mr. L is a bit different. He uses a set of three chopsticks -- one pair, plus an EXTRA long chopstick to get some big food by piercing it through the food. As you may guess, the length of the two shorter chopsticks should be as close as possible, but the length of the extra one is not important, as long as it's the longest. To make things clearer, for the set of chopsticks with lengths A,B,C(A<=B<=C), (A-B)2 is called the 'badness' of the set.
It's December 2nd, Mr.L's birthday! He invited K people to join his birthday party, and would like to introduce his way of using chopsticks. So, he should prepare K+8 sets of chopsticks(for himself, his wife, his little son, little daughter, his mother, father, mother-in-law, father-in-law, and K other guests). But Mr.L suddenly discovered that his chopsticks are of quite different lengths! He should find a way of composing the K+8 sets, so that the total badness of all the sets is minimized.
Input
The first line in the input contains a single integer T, indicating the number of test cases(1<=T<=20). Each test case begins with two integers K, N(0<=K<=1000, 3K+24<=N<=5000), the number of guests and the number of chopsticks. There are N positive integers Li on the next line in non-decreasing order indicating the lengths of the chopsticks.(1<=Li<=32000).
Output
For each test case in the input, print a line containing the minimal total badness of all the sets.
Sample Input
11 40
1 8 10 16 19 22 27 33 36 40 47 52 56 61 63 71 72 75 81 81 84 88 96 98 103 110 113 118 124 128 129 134 134 139 148 157 157 160 162 164
Sample Output
23Note
For the sample input, a possible collection of the 9 sets is:8,10,16; 19,22,27; 61,63,75; 71,72,88; 81,81,84; 96,98,103; 128,129,148; 134,134,139; 157,157,160
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參考 http://www.cppblog.com/rakerichard/archive/2010/02/19/108081.html
網路上蒐的另外一個用 for 迴圈跑的,
http://www.cppblog.com/syhd142/articles/118232.html
我感到疑惑, 對於 1 個人的化, 那個做法是錯誤的
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define oo 100000000
int DP[1010][5001];
int L[5001], bad[5001];
int cmp(const void *i, const void *j) {
return *(int *)j - *(int *)i;
}
int min(int x, int y) {
return x < y ? x : y;
}
int findDP(int k, int n) {
if(DP[k][n] != -1)
return DP[k][n];
if(n < 3*k) {
DP[k][n] = oo;
} else if(k == 0) {
DP[k][n] = 0;
} else {
DP[k][n] = min(findDP(k, n-1), findDP(k-1, n-2)+bad[n]);
}
return DP[k][n];
}
int main() {
int t, n, k, i, j;
scanf("%d", &t);
while(t--) {
scanf("%d %d", &k, &n);
for(i = 1; i <= n; i++)
scanf("%d", &L[i]);
k += 8;
qsort(L+1, n, sizeof(int), cmp);
for(i = 2; i <= n; i++)
bad[i] = (L[i]-L[i-1])*(L[i]-L[i-1]);
for(i = 0; i <= k; i++)
for(j = 0; j <= n; j++)
DP[i][j] = -1;
printf("%d\n", findDP(k, n));
}
return 0;
}