HDU 1051 Wooden Sticks 贪心||DP
rep code 子列 iss miss minimum span mission
Wooden Sticks
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 22000 Accepted Submission(s): 8851
Problem Description
There is a pile of n wooden sticks. The length and weight of each stick are known in advance. The sticks are to be processed by a woodworking machine in one by one fashion. It needs some time, called setup time, for the machine to prepare processing a stick. The setup times are associated with cleaning operations and changing tools and shapes in the machine. The setup times of the woodworking machine are given as follows:
(a) The setup time for the first wooden stick is 1 minute.
(b) Right after processing a stick of length l and weight w , the machine will need no setup time for a stick of length l'and weight w' if l<=l' and w<=w'. Otherwise, it will need 1 minute for setup.
You are to find the minimum setup time to process a given pile of n wooden sticks. For example, if you have five sticks whose pairs of length and weight are (4,9), (5,2), (2,1), (3,5), and (1,4), then the minimum setup time should be 2 minutes since there is a sequence of pairs (1,4), (3,5), (4,9), (2,1), (5,2).
Input
The input consists of T test cases. The number of test cases (T) is given in the first line of the input file. Each test case consists of two lines: The first line has an integer n , 1<=n<=5000, that represents the number of wooden sticks in the test case, and the second line contains n 2 positive integers l1, w1, l2, w2, ..., ln, wn, each of magnitude at most 10000 , where li and wi are the length and weight of the i th wooden stick, respectively. The 2n integers are delimited by one or more spaces.
Output
The output should contain the minimum setup time in minutes, one per line.
Sample Input
3
5
4 9 5 2 2 1 3 5 1 4
3
2 2 1 1 2 2
3
1 3 2 2 3 1
Sample Output
Source
Asia 2001, Taejon (South Korea)
思路:将木棒按 l,w 递减的顺序排列,统计关于递减的连续子列的个数即为答案。
代码:
- 1#include "cstdio"2#include "iostream"3#include "algorithm"4#include "string"5#include "cstring"6#include "queue"7#include "cmath"8#include "vector"9#include "map"10#include "stdlib.h"11#include "set"12#define mj 13#define db double 14#define ll long long 15 using namespace std;
- 16 const int N = 1e6 + 5;
- 17 const int mod = 1e9 + 7;
- 18 const ll inf = 1e16 + 10;
- 19 bool u[N];
- 20 typedef struct stu {
- 21 int l,
- w;
- 22
- }
- M;
- 23 M s[5005];
- 24 int cmp(M a, M b) 25 {
- 26
- if (a.l == b.l) return a.w >= b.w;
- 27
- return a.l >= b.l;
- 28
- }
- 29 int main() 30 {
- 31 int t,
- n,
- i,
- j,
- ans;
- 32 scanf("%d", &t);
- 33
- while (t--) 34 {
- 35 scanf("%d", &n);
- 36
- for (i = 0; i) 37 scanf("%d%d", &s[i].l, &s[i].w),
- u[i] = 0;
- 38 sort(s, s + n, cmp);
- 39 int mi;
- 40 ans = 0;
- 41
- for (i = 0; i) 42 {
- 43
- if (u[i]) continue;
- 44 mi = s[i].w;
- 45
- for (j = i + 1; j) 46 {
- 47
- if (!u[j] && s[j].w <= mi) {
- 48 mi = s[j].w;
- 49 u[j] = 1;
- 50
- }
- 51
- }
- 52 ans++;
- 53
- }
- 54 printf("%d\n", ans);
- 55
- }
- 56
- return 0;
- 57
- }
HDU 1051 Wooden Sticks 贪心 ||DP
来源: http://www.bubuko.com/infodetail-2165251.html