I have WA on test 8. Can someone help. I tried every given test in the site but I can't find any mistakes.
This is my code:
//
#include<iostream>
#include<cmath>
#include<algorithm>
#include<iomanip>
using namespace std;
bool b[2005][2005];
long double a[2005][2005];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    long double diag=sqrt(2)*100;
    int n,m,k,k1,r;
    cin>>n>>m>>r;
    for(int i=0;i<r;i++)
    {
        cin>>k>>k1;
        b[k][k1]=1;
    }
    n++;
    m++;
    for(int i=2;i<=n;i++)a[1][i]=a[1][i-1]+100;
    for(int i=2;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            a[i][j]=a[i-1][j]+100;
            if(j!=1 && a[i][j]>a[i][j-1]+100)a[i][j]=a[i][j-1]+100;
            if(b[i-1][j-1] && a[i][j]>a[i-1][j-1]+diag+0.001)a[i][j]=a[i-1][j-1]+diag;
        }
    }
    cout<<fixed<<setprecision(0)<<a[n][m]<<"\n";
    return 0;
}