求解菲波那切数列算法耗时比较

使用传统递归算法和记忆化搜索算法的耗时比较

#include <ctime>
#include <cstdio>
#include "algorithm"

using namespace std;
int dp[1000];
clock_t start, finish;
double duration;

int F1(int n) {
    if (n == 1 || n == 0)
        return 1;
    else
        return F1(n - 1) + F1(n - 2);
}

int F2(int n) {
    if (n == 1 || n == 0)
        return 1;
    else if (dp[n] != -1)
        return dp[n];
    else {
        dp[n] = F2(n - 1) + F2(n - 2);
        return dp[n];
    }

}

int main() {
    fill(dp, dp + 1000, -1);
    start = clock();
    int d1 = F1(40);
    finish = clock();
    duration = (double) (finish - start) / CLOCKS_PER_SEC;
    printf("%f seconds\n", duration);

//记忆化搜索
    start = clock();
    int d2 = F2(40);
    finish = clock();
    duration = (double) (finish - start) / CLOCKS_PER_SEC;
    printf("%f seconds\n", duration);

    printf("d1:%d d2:%d", d1, d2);

}

耗时：