POJ 1579 Function Run Fun 记忆化递归
2010-12-15 21:04
585 查看
本题使用记忆话递归即可,也可以用动态规划DP
不过得使用三维数组,空间复杂度比较高
Function Run Fun
Time Limit: 1000MS | Memory Limit: 10000 |
We all love recursion! Don't we?
Consider a three-parameter recursive function w(a, b, c):
if a <= 0 or b <= 0 or c <= 0, then w(a, b, c) returns:
1
if a > 20 or b > 20 or c > 20, then w(a, b, c) returns:
w(20, 20, 20)
if a < b and b < c, then w(a, b, c) returns:
w(a, b, c-1) + w(a, b-1, c-1) - w(a, b-1, c)
otherwise it returns:
w(a-1, b, c) + w(a-1, b-1, c) + w(a-1, b, c-1) - w(a-1, b-1, c-1)
This is an easy function to implement. The problem is, if implemented directly, for moderate values of a, b and c (for example, a = 15, b = 15, c = 15), the program takes hours to run because of the massive recursion.
Input
The input for your program will be a series of integer triples, one per line, until the end-of-file flag of -1 -1 -1. Using the above technique, you are to calculate w(a, b, c) efficiently and print the result.
Output
Print the value for w(a,b,c) for each triple.
Sample Input
1 1 1 2 2 2 10 4 6 50 50 50 -1 7 18 -1 -1 -1
Sample Output
w(1, 1, 1) = 2 w(2, 2, 2) = 4 w(10, 4, 6) = 523 w(50, 50, 50) = 1048576 w(-1, 7, 18) = 1
/* Author yan *POJ 1579 *Function Run Fun */ #include<stdio.h> int value[61][61][61]; int w(int a,int b,int c) { if(value[a+10][b+10][c+10]!=-1) return value[a+10][b+10][c+10]; else { if(a<=0||b<=0||c<=0) return value[a+10][b+10][c+10]=1; else if(a>20||b>20||c>20) return value[a+10][b+10][c+10]=w(20,20,20); else if(a<b&&b<c) return value[a+10][b+10][c+10]=w(a,b,c-1)+w(a,b-1,c-1)-w(a,b-1,c); else return value[a+10][b+10][c+10]=w(a-1,b,c)+w(a-1,b-1,c)+w(a-1,b,c-1)-w(a-1,b-1,c-1); } } int main() { int a,b,c; //freopen("input","r",stdin); while(scanf("%d %d %d",&a,&b,&c)&&(a!=-1||b!=-1||c!=-1)) { memset(value,-1,sizeof(value)); //printf("%d %d %d/n",a,b,c); printf("w(%d, %d, %d) = ",a,b,c); if(a<=0||b<=0||c<=0) printf("%d/n",1); else { w(a,b,c); printf("%d/n",value[a+10][b+10][c+10]); } } return 0; }
相关文章推荐
- POJ 1579 Function Run Fun 记忆化递归
- POJ 1579 Function Run Fun 记忆化递归
- POJ 1579 Function Run Fun 记忆化递归
- 【poj1579】Function Run Fun (动态规划DP递归,记忆化递归)
- POJ1579:Function Run Fun(记忆化)
- POJ:1579 Function Run Fun(递归转换+打表)
- POJ1579——Function Run Fun(记忆化递归)
- poj 1579 Function Run Fun 递归
- POJ - 1579:Function Run Fun(递归,记忆化搜索)
- POJ 1579-Function Run Fun(记忆化搜索-递归)
- POJ 1579 Function Run Fun 记忆化搜索
- POJ 1579 Function Run Fun【递归转循环】
- POJ-1579-Function Run Fun-递归,记忆化搜索
- POJ 题目1579 Function Run Fun(记忆搜索)
- POJ 1579 记忆化递归
- poj - 1579 Function Run Fun 【dp】
- 记忆化搜索:POJ1579-Function Run Fun(最基础的记忆化搜索)
- Function Run Fun POJ - 1579 记忆化搜索
- POJ 1579-Function Run Fun(记忆化搜索)
- 记忆化递归搜索(poj 1579)