[HDOJ5417]Victor and Machine

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <cmath>
#include <queue>
#include <deque>
#include <map>
#include <stack>
#include <list>
#include <vector>
#include <ctime>

using namespace std;

int x,y,w,n;

int main(){    
    while(~scanf("%d%d%d%d", &x, &y, &w, &n)) {
        int t;
        int ans = 1;
        int cnt = 1;
        while(1) {
            if(cnt == n) {
                break;
            }
            t = ans % (x + y);
            if(t == 0) {
                cnt++;
            }
            else if(t <= x && x >= w && t % w == 0) {
                cnt++;
            }
            ans++;
        }
        printf("%d\n", ans - 1);
    }
    return 0;
}