zoj 2853 Evolution
Evolution is a long, long process with extreme complexity and involves many species. Dr. C. P. Lottery is currently investigating a simplified model of evolution: consider that we have N (2 <= N <= 200) species in the whole process of evolution, indexed from 0 to N -1, and there is exactly one ultimate species indexed as N-1. In addition, Dr. Lottery divides the whole evolution process into M (2 <= M <= 100000) sub-processes. Dr. Lottery also gives an 'evolution rate' P(i, j) for 2 species i and j, where i and j are not the same, which means that in an evolution sub-process, P(i, j) of the population of species i will transform to species j, while the other part remains unchanged.
Given the initial population of all species, write a program for Dr. Lottery to determine the population of the ultimate species after the evolution process. Round your final result to an integer.
Input
The input contains multiple test cases!
Each test case begins with a line with two integers N, M. After that, there will be a line with N numbers, indicating the initial population of each species, then there will be a number T and T lines follow, each line is in format "i j P(i,j)" (0 <= P(i,j) <=1).
A line with N = 0 and M = 0 signals the end of the input, which should not be proceed.
Output
For each test case, output the rounded-to-integer population of the ultimate species after the whole evolution process. Write your answer to each test case in a single line.
Notes
- There will be no 'circle's in the evolution process.
- E.g. for each species i, there will never be a path i, s1, s2, ..., st, i, such that P(i,s1) <> 0, P(sx,sx+1) <> 0 and P(st, i) <> 0.
- The initial population of each species will not exceed 100,000,000.
- There're totally about 5 large (N >= 150) test cases in the input.
Example
Let's assume that P(0, 1) = P(1, 2) = 1, and at the beginning of a sub-process, the populations of 0, 1, 2 are 40, 20 and 10 respectively, then at the end of the sub-process, the populations are 0, 40 and 30 respectively.
Sample Input
2 3
100 20
1
0 1 1.0
4 100
1000 2000 3000 0
3
0 1 0.19
1 2 0.05
0 2 0.67
0 0
Sample Output
120
0
Author: JIANG, Jiefeng
Source: Zhejiang Provincial Programming Contest 2007
//1868191 2009-05-14 09:56:25 Wrong Answer 2853 C++ 3870 1472 Wpl
//1868298 2009-05-14 10:59:02 Accepted 2853 C++ 3900 1472 Wpl
#include <iostream>
#define MAX 203
using namespace std;
typedef struct node
{
double matrix[MAX][MAX];
}Matrix;
Matrix unit,init,result,c;
int n,m,t;
double data[MAX];
void Init()
{
int i,j;
double p;
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
init.matrix[i][j]=(i==j); //相当于init刚开始默认全部由自己进化到自己
unit.matrix[i][j]=(i==j); //单位矩阵
}
for(i=0;i<n;i++)
scanf("%lf",&data[i]);
scanf("%d",&t);
while(t--)
{
scanf("%d%d%lf",&i,&j,&p);
//init.matrix[i][j]+=p; //why wrong?????
//init.matrix[i][i]-=p;
init.matrix[j][i]+=p;
init.matrix[i][i]-=p;
}
}
void Cal(int exp)
{
int i,j,k;
if(exp==1)
result=init;
while(exp!=1)
{
if(exp&1)
{
exp--;
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
c.matrix[i][j]=0;
for(k=0;k<n;k++)
c.matrix[i][j]+=init.matrix[i][k]*unit.matrix[k][j];
}
unit=c;
}
else
{
exp>>=1;
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
c.matrix[i][j]=0;
for(k=0;k<n;k++)
c.matrix[i][j]+=init.matrix[i][k]*init.matrix[k][j];
}
init=c;
}
}
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
result.matrix[i][j]=0;
for(k=0;k<n;k++)
result.matrix[i][j]+=unit.matrix[i][k]*init.matrix[k][j];
}
}
int main()
{
int i,j;
double r;
while(scanf("%d%d",&n,&m)!=EOF)
{
if(n==0&&m==0)
break;
Init();
Cal(m); //求初始矩阵的m次幂
r=0;
for(j=0;j<n;j++)
r+=result.matrix[n-1][j]*data[j];
printf("%.0lf\n",r);
}
return 0;
}
