Count pairs Sum in matrices

class Solution {
    int countPairs(int mat1[][], int mat2[][], int n, int x) {
        // Code Here
        int r1=0,c1=0;
        int r2=n-1,c2=n-1;
        int ans=0;
        while(r1<n && r2>=0){
            int sum=mat1[r1][c1]+mat2[r2][c2];
            if(sum==x){
                ans++;
                c1++;
                c2--;
            }
            if(sum<x){
                c1++;
            }
            if(sum>x){
                c2--;
            }
            if(c1==n){
                c1=0;
                r1++;
            }
            if(c2==-1){
                c2=n-1;
                r2--;
            }
        }
        return ans;
    }
}