firstMissingPositive

int firstMissingPositive(int A[], int n) {    int max = 0, min =0, sum=0;    for(int i=0; i<n; i++){      if(A[i]>0)sum+=A[i];      if(A[i]>max) max = A[i];    }    if(n==0)        return 1;    int missing = (double)(1+max)/2*(max)-sum;    return missing==0?(max+1):missing;}

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