为什么只有10分？

#include <cstdio>
#include <cmath>
#ifdef __GNUC__
#include <algorithm>
#define gcd __gcd
#else
inline int gcd(int a, int b){
    return (b == 0 ? a : gcd(b, a % b));
}
#endif
using namespace std;
int sq[5000005];
int P, Q;
void init_sq(int m){
    int i, j, k;
    const int M = (m<<2) + m;  // <= m^2 - 4*m*(-m) = 5 * m^2
    const int S = floor(sqrt(M));
    sq[1] = 1;
    for (i=2; i<=S; i++){
        //if (sq[i]) continue;
        j = i*i;
        for (k=j; k<=M; k+=j)
            sq[k] = i;
    }
}
void gpq(int c, int d){
    if (d == 0) return;
    if (c == 0){
        P = 0, Q = 1;
        return;
    }
    short s = 1;
    if (d < 0) c = -c, d = -d;
    if (c < 0) c = -c, s = -1;
    int g = gcd(c, d);
    int p = c / g, q = d / g;
    P = s*p, Q = q;
}
bool opr(int c, int d, bool oz = 1){
    gpq(c, d);
    if (P == 0 && !oz) return 0;
    if (Q == 1) printf("%d", P);
    else printf("%d/%d", P, Q);
    return 1;
}
inline int delta(int a, int b, int c){
    return b*b - ((a*c)<<2);
}
int main()
{
    int t, m, a, b, c, d, k;
    scanf("%d%d", &t, &m);
    init_sq(m*m);
    while (t--){
        scanf("%d%d%d", &a, &b, &c);
        d = delta(a, b, c);
        if (d < 0){
            puts("NO");
            continue;
        }
        a <<= 1;
        if (d == 0){
            opr(-b, a);
            puts("");
            continue;
        }
        if (sq[d] == 0){
            if (opr(-b, a, 0)) putchar('+');
            printf("sqrt(%d)/%d\n", d, a);
            continue;
        }
        k = sq[d];
        d /= k*k;
        if (d == 1){
            opr(k-b, a);
            puts("");
            continue;
        }
        bool f = opr(-b, a, 0);
        gpq(k, a);
        if (P != 1){
            if (P > 0 && f) putchar('+');
            printf("%d*", P);
        }
        if (P == 1 && f) putchar('+');
        printf("sqrt(%d)", d);
        if (Q != 1)
            printf("/%d", Q);
        puts("");
    }
    return 0;
}