题目大意:有两组什么东西,题目背景有点忘记了,就是给出两组数,两组个数分别为n,m,要求找出min(n,m)对数。每一个数最多最多选一次,使得这min(n,m)对数ai,bi。ai-bi的绝对值之和最小。
解题思路:贪心。将两组数分别排序,然后dp[i][j]表示i对,匹配到j时候的最优解。
#include <cstdio> #include <cstring> #include <cmath> #include <algorithm> using namespace std; const int N = 505; int n, m; double cn[N], cm[N], dp[N][N]; void init () { scanf("%d%d", &n, &m); for (int i = 0; i < n; i++) scanf("%lf", &cn[i]); for (int i = 0; i < m; i++) scanf("%lf", &cm[i]); sort(cn, cn + n); sort(cm, cm + m); if (n > m) { double tmp[N]; memcpy(tmp, cm, m*sizeof(double)); memcpy(cm, cn, n*sizeof(double)); memcpy(cn, tmp, m*sizeof(double)); swap(n, m); } } double solve () { dp[0][0] = fabs(cn[0] - cm[0]); for (int i = 1; i < m; i++) dp[0][i] = min (fabs(cn[0]-cm[i]), dp[0][i-1]); for (int i = 1; i < n; i++) { dp[i][i] = dp[i-1][i-1] + fabs(cn[i]-cm[i]); for (int j = i+1; j < m; j++) dp[i][j] = min (dp[i-1][j-1] + fabs(cn[i] - cm[j]), dp[i][j-1]); } return dp[n-1][m-1]; } int main () { int cas; scanf("%d", &cas); while (cas--) { init (); printf("%.1lf ", solve()); } return 0; }
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