Problem 0004 : Simultaneous Equation
#include <iostream>
#include <iomanip>
using namespace std;
#define N 2
int main(void)
{
double a[N][N+1];
int i, j, k;
for( i=0; i<N; i++ ){
for( j=0; j<N+1; j++ ){
cin >> a[i][j];
}
}
double p, d;
for( k=0; k<N; k++ ){
p = a[k][k];
for( i=0; i<N+1; i++ )
a[k][i] /= p;
for( i=0; i<N; i++ ){
if( i != k ){
d = a[i][k];
for( j=0; j<N+1; j++ ){
a[i][j] -= a[k][j]*d;
}
}
}
}
cout << setprecision(3) << setiosflags(ios::fixed);
cout << a[0][N] << " " << a[1][N] << endl;
return 0;
}
Problem 0006 : Reverse Sequence
#include <iostream>
#include <string>
using namespace std;
std::string reverse( std::string src ){
std::string str = src;
for( int i=0; i<src.size(); i++ )
str[i] = src[src.size()-1-i];
return str;
}
int main(void){
string str;
cin >> str;
cout << reverse(str) << endl;
return 0;
}
Problem 0007 : Dept Hell
#include <iostream>
using namespace std;
int main(void){
int n;
cin >> n;
int m = 100000;
int i;
for( i=0; i<n; i++ ){
m = (double)m*1.05;
if( m%1000 ){
m += 1000; m -= m%1000;
}
}
cout << m << endl;
return 0;
}
Problem 0008 : Sum of 4 Integers
#include <iostream>
using namespace std;
int n, cnt;
void calc( int n, int sum, int level ){
if( level == 4 ){
if( sum == n ){
cnt++;
}
return;
}
int i;
for( i=0; i<=9; i++ ){
calc( n, sum+i, level+1 );
}
return;
}
int main(void)
{
while( cin >> n ){
cnt = 0;
calc( n, 0, 0 );
cout << cnt << endl;
}
return 0;
}