动态规划总结

1.斐波那契数列的动规写法（避免递归树重复计算）

<pre name="code" class="cpp">#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <numeric>
#include <cstring>
#include <climits>
#include <cassert>
#include <complex>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>
using namespace std;

#pragma comment(linker, "/STACK:102400000,102400000")

typedef long long LL;
typedef double DB;
typedef unsigned uint;
typedef unsigned long long uLL;

/** Constant List .. **/ //{

const int MOD = int(1e9)+7;
const int INF = 0x3f3f3f3f;
const LL INFF = 0x3f3f3f3f3f3f3f3fLL;
const DB EPS = 1e-9;
const DB OO = 1e20;
const DB PI = acos(-1.0); //M_PI;
const int maxn = 100001;
int f[maxn];
int n;

int fib(int n)
{
    if(f[n] != 0)
        return f[n];
    if(n == 0)
        return 0;
    else if(n == 1)
        return 1;
    else
    {
        f[n] = fib(n-1) + fib(n-2);
        return f[n];
    }
}

int main()
{
    #ifdef DoubleQ
    freopen("in.txt" , "r" , stdin);
    #endif;
    while(~scanf("%d",&n))
    {
        memset(f , 0  , sizeof(f));
        cout << fib(n) << endl;
    }

}
<pre name="code"