Using C language to realize permutation and combination (one of the interview questions of Huawei software)

/Leave nX = m*n-x from the remaining nM baskets; Ball

int get ball (int NX, int nm, int n) {int na; int nS = ;

/* If it is determined that the ball is empty from a basket in this case *///If nM is equal to 1, return 1; if (nX < = n) {

/* Take it from at least one basket, and at most take it from a few baskets among nM and n */

// When nA increases from 1 to nX, execute the following statement ns+= getball (na, 1, n)+getball (NX-na, nm-1, n) circularly;

// returnS ns; } else if (nX > N) {

/* 1. Know the number of remaining baskets nM, 2. Ensure NX-na <; = nm * n */

/When nA decreases from n to nX-n*nM, the following statement NS+= getball (na, 1, n)+getball (NX-na, nm-1, n) is executed circularly;

// returnS ns; }

}

int main() { int m,n,x; m = 5; n = 6; x = 22; printf("%d\n",GetBall(m*n-x, m, n)); return ;

}