ACM-ICPC基本算法之递推法

#include <iostream>
using namespace std;
int main()
{
    int i,n,preNum = 1,curNum = 1,temp;
    cin >> n;
    for(i = 3;i <= n;i++)
    {
        temp = curNum;
        curNum = curNum + preNum;
        preNum = temp;
    }
    cout << curNum << endl;
    return 0;
}

#include <iostream>
using namespace std;
int gcd(int a, int b)
{
    while(b>0)
    {
        int temp = a % b;
        a = b;
        b = temp;
    }
    return a;
}
int main()
{
    int m,n;
    cin >> m >> n;
    cout << gcd(m,n) << endl;
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int i,n;
    while(cin >> n && n){
        int sum = 1;
        for(i = 2;i <= n;i++)
            sum = (sum+1)*2;
        cout << sum << endl;
    }
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int i,j,n,a[35][35];
    cin >> n;
    for(i = 0;i < n;i++)
    {
        a[i][0] = 1;
        a[i][i] = 1;
        for(j = 1;j < i;j++)
            a[i][j] = a[i-1][j-1] + a[i-1][j];
    }
    for(i = 0;i < n;i++)
    {
        for(j = 0;j <= i;j++)
            cout << a[i][j];
        cout << endl;
    }
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int x,k=1;
    double oil,dis = 500;
    cin >> x;
    if(x <= 500)
        oil = x;
    else
    {
        do
        {
            ++k;
            dis += 500.0/(2*k-1);
            oil = 500*k;
        }
        while(dis<x);
        oil = 500*k + (x-dis)*(2*k-1);
    }
    printf("%.2f\n",oil);
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int n,i;
    long long a[51];
    a[1] = 3;
    a[2] = 6;
    a[3] = 6;
    for(i=4;i<51;i++)
        a[i] = 2*a[i-1]+a[i-1];
    while(cin >> n && n)
        cout << a[n] << endl;
    return 0;
}