/* Pre: perm is initialized, hist[0..rank-1] is descending.
* Create the list of permutations (as powers of 2)
* that preserve hist[0..rank-1] */
Arraylist specPerm(int rank, int* hist) {
int i, j, k, m, x;
Intstack prim = newIntstack(rank, NULL) ;
Arraylist result = newArraylist(1) ;
Arraylist locperm;
prim->size = rank;
for (i = 0, x = 1; i < rank; i++, x <<= 1) {
prim->it[i] = x;
}
putItem(prim, result) ;
i = 0;
while (i + 1 < rank) {
j = i+1;
while (j < rank && hist[i] == hist[j])
j++;
if (i+1 < j) {
x = result->size;
locperm = getPerm(j-i) ;
for (k = 0; k < locperm->size - 1; k++)
for (m = 0; m < x; m++)
putItem(applyPerm(i, result->it[m], locperm->it[k]), result) ;
}
i = j;
}
return result;
}
Arraylist getPerm(int rank) {
int i, j, k;
Intstack y, z;
if (!permInit)
initPerm() ;
if (perm[rank] != NULL)
return perm[rank];
if (perm[rank-1] == NULL)
getPerm(rank-1) ;
perm[rank] = newArraylist(rank * perm[rank-1]->size) ;
for (i = 0; i < perm[rank-1]->size; i++) {
y = perm[rank-1]->it[i];
for (j = 0; j < rank; j++) {
z = newIntstack(rank, NULL);
for (k = 0; k < j; k++)
z->it[k] = y->it[k];
z->it[j] = rank - 1;
for (k = j; k < y->size; k++)
z->it[k+1] = y->it[k];
z->size = rank;
putItem(z, perm[rank]) ;
}
}
return perm[rank];
}
vector<vector<int> > permuteUnique(vector<int> &num) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
vector<vector<int>> ret;
int cnt = num.size();
if(!cnt) return ret;
bool avl[cnt];
memset(avl,1,sizeof(bool)*cnt);
sort(num.begin(),num.end());
vector<int> temp;
getPerm(ret,num,temp,avl);
return ret;
}
void getPerm(vector<vector <int>> &ret, vector<int> &num, vector<int> &temp,bool * avl){
int cnt = num.size();
if(temp.size()==cnt){
ret.push_back(temp);
return;
}
for(int i=0;i<cnt;i++){
if(avl[i] && (i==0 || (num[i]==num[i-1]&& !avl[i-1]) ||(num[i]!=num[i-1]) ) ){
//forget to consider how about the first layer not work but the second layer work.
//to handle this, see if i was used or not
//if not use, it means it's a parrale branch
//otherwise it used
temp.push_back(num[i]);
avl[i]=false;
getPerm(ret,num,temp,avl);
temp.pop_back();
avl[i]=true;
}
}
}
void printPerm(int rank) {
getPerm(rank) ;
mapar(perm[rank], (void (*)(void*)) printCell) ;
}
