ZOJ 3647 Gao the Grid

dp一下吧~简单的组合数学题

#include<iostream>#include<vector>#include<algorithm>#include<cstdio>#include<queue>#include<stack>#include<string>#include<map>#include<set>#include<cmath>#include<cassert>#include<cstring>#include<iomanip>using namespace std;#ifdef _WIN32#define i64 __int64#define out64 "%I64d\n"#define in64 "%I64d"#else#define i64 long long#define out64 "%lld\n"#define in64 "%lld"#endif/************ for topcoder by zz1215 *******************/#define FOR(i,a,b)      for( int i = (a) ; i <= (b) ; i ++)#define FFF(i,a)        for( int i = 0 ; i < (a) ; i ++)#define FFD(i,a,b)      for( int i = (a) ; i >= (b) ; i --)#define S64(a)          scanf(in64,&a)#define SS(a)           scanf("%d",&a)#define LL(a)           ((a)<<1)#define RR(a)           (((a)<<1)+1)#define pb              push_back#define CL(Q)           while(!Q.empty())Q.pop()#define MM(name,what)   memset(name,what,sizeof(name))#define MC(a,b)memcpy(a,b,sizeof(b))#define MAX(a,b)        ((a)>(b)?(a):(b))#define MIN(a,b)        ((a)<(b)?(a):(b))#define read            freopen("in.txt","r",stdin)#define write           freopen("out.txt","w",stdout)const int inf = 0x3f3f3f3f;const i64 inf64 = 0x3f3f3f3f3f3f3f3fLL;const double oo = 10e9;const double eps = 10e-9;const double pi = acos(-1.0);const int maxn = 1001;int n,m;i64 dp[maxn][maxn];i64 s[maxn][maxn];int gcd(int _a, int _b){    if (!_a || !_b)    {        return max(_a, _b);    }    int _t;    while ((_t = _a % _b))    {        _a = _b;        _b = _t;    }    return _b;}void init(){dp[0][0]=0;s[0][0]=0;for(int i=1;i<maxn;i++){dp[0][i]=0;s[0][i]=0;dp[i][0]=0;s[i][0]=0;}int temp;for(int i=1;i<maxn;i++){for(int j=1;j<maxn;j++){temp = gcd(i,j);dp[i][j]=dp[i][j-1]+dp[i-1][j]-dp[i-1][j-1]+temp-1;}}for(int i=1;i<maxn;i++){for(int j=1;j<maxn;j++){s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+dp[i][j];}}return ;}i64 find(){i64 re=0;i64 temp;temp = n+1;temp*= m+1;temp = temp*(temp-1)*(temp-2);temp/= 6;re = temp;re -= s[n][m];re -= s[m][n];temp = n+1;temp = temp*(temp-1)*(temp-2);temp/=6;temp*= m+1;re -= temp;temp = m+1;temp = temp*(temp-1)*(temp-2);temp /=6;temp*=n+1;re -= temp;return re;}int main(){init();while(cin>>n>>m){cout<<find()<<endl;}return 0;}