Wooden Sticks---hdu1051(最长上升子序列)
http://acm.hdu.edu.cn/showproblem.php?pid=1051
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).
(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
2 1 3
这道题刚开始并不知道怎么写 丝毫没有思路 后来发现这不就是上升子序列么
但是还是忘了怎么写 就翻了之前的博客有调试一下才看懂
发现真是学的不快忘得挺快 唉
#include<stdio.h> #include<string.h> #include<algorithm> #include<queue> using namespace std; #define N 5500 struct node { int u,v; }a[N]; int cmp(const void *x,const void *y) { struct node *c,*d; c=(struct node *)x; d=(struct node *)y; if(c->u!=d->u) return d->u-c->u; else return d->v-c->v; } int main() { int T,n; scanf("%d",&T); while(T--) { scanf("%d",&n); for(int i=0;i<n;i++) { scanf("%d %d",&a[i].u,&a[i].v); } qsort(a,n,sizeof(a[0]),cmp); int dp[N]; int Max=0; for(int i=0;i<n;i++) { dp[i]=1; for(int j=0;j<i;j++) { if(a[i].v>a[j].v && dp[j]+1>dp[i]) dp[i]=dp[j]+1; } if(dp[i]>dp[Max]) Max=i; } printf("%d\n",dp[Max]); } return 0; }