HDU 2513 Cake slicing

#include<bits/stdc++.h>
using namespace std;
int n,m,k;
int cherry[405],dp[405][405];
int solve(int l,int r)
{
    //printf("%d,%d %d,%d\n",l/m,l%m,r/m,r%m);
    int &ret=dp[l][r];
    if(ret!=-1)return ret;
    int nmin=30,nmax=-1,mmin=30,mmax=-1;
    for(int i=1;i<=k;++i)
    {
        int ntmp=cherry[i]/m,mtmp=cherry[i]%m;
        if(ntmp>=l/m&&ntmp<=r/m&&mtmp>=l%m&&mtmp<=r%m)nmin=min(nmin,ntmp),nmax=max(nmax,ntmp),mmin=min(mmin,mtmp),mmax=max(mmax,mtmp);
    }
    if(nmin==-1)ret=0;
    if(nmin==nmax&&mmin==mmax)ret=0;
    if(ret==0)return ret;
    ret=0x3f3f3f3f;
    for(int i=nmin;i<nmax;++i)ret=min(ret,solve(l,r-(r/m-i)*m)+solve(l+(i-l/m+1)*m,r)+(r%m-l%m+1));
    for(int i=mmin;i<mmax;++i)ret=min(ret,solve(l,r-(r%m-i))+solve(l+(i-l%m+1),r)+(r/m-l/m+1));
    return ret;
}
int main()
{
    int Case=0;
    while(~scanf("%d%d%d",&n,&m,&k))
    {
        memset(dp,-1,sizeof dp);
        for(int i=1;i<=k;++i){int a,b;scanf("%d%d",&a,&b);cherry[i]=a*m-m+b-1;}
        printf("Case %d: %d\n",++Case,solve(0,n*m-1));
    }
}