遞迴

f(n){ f(n-1) }

遞迴

/*
 * AP325
 * P-1-1. 合成函數(1)
*/
#include<bits/stdc++.h>
using namespace std;

int solve(){
	string s;
	cin >> s;
	if(s[0]=='f'){
		int x = solve();
		return 2*x-1;
	}else if(s[0]=='g'){
		int x = solve();
		int y = solve();
		return x+2*y-3;
	}else{
		int sum = 0;
		for(int i=0;i<s.size();++i){
			sum+=s[i]-'0';
			sum*=10;
		}
		return sum/10;
	}
}

int main(){
	cout << solve() << endl;
}

河內塔

/*
 * TIOJ
 * 1355. 河內之塔-蘿莉塔
*/
#include<bits/stdc++.h>
using namespace std;

int cnt = 0;

void f(int n, int from, int temp, int to) {
    if (n == 1) {
        cnt += 1;
        printf("#%d : move the dish from #%d to #%d\n", cnt, from, to);
        return;
    }
    f(n - 1, from, to, temp); 
    cnt += 1;
    printf("#%d : move the dish from #%d to #%d\n", cnt, from, to);
    f(n - 1, temp, from, to);
}

int main() {
    int n;
    cin >> n;
    f(n, 1, 2, 3);
}