[PS][DP]/[BOJ][2193][이친수]

boj2193.cpp

#include <iostream>

using namespace std;

int n = 0;
long long dp[91][2];

int main(void) {
	int n = 0;
	cin >> n;	
	dp[1][0] = 0;
	dp[1][1] = 1;
	for (int i = 2; i <= n; i++) {
		dp[i][0] = dp[i - 1][0] + dp[i - 1][1];
		dp[i][1] = dp[i - 1][0];
	}
	cout << dp[n][0] + dp[n][1];
	return 0;
}