public class FindSubstrs {

static void findSubstrs(char[] s, char[] pat) {

int[] need = new int[26];

int[] found = new int[26];

char[] pat = pattern.toCharArray();

for(char c: pat) need[c - 'a'] += 1;

int n = s.length();

List<Integer> re = new ArrayList<> ();

int len = 0;

int sum = 0;

int l = 0, r = 0;

for(; r<n; ++r) {

char c = s[r];

int v = c - 'a';

sum = (sum + v) % pat.length;

mod[sum] += 1;

found[s[r] - 'a'] += 1;

if(found[s[r] - 'a'] <= need[s[r] - 'a']) len += 1;

if(len == pat.length) {

while(l <= r && (need[s[l] - 'a'] == 0 || found[s[l] - 'a'] > need[s[l] - 'a'])) {

if(found[s[l] - 'a'] > need[s[l] - 'a']) found[s[l] - 'a'] -= 1;

l += 1;

}

if(r-l+1 == pat.length) {

re.add(l);

}

}

} // end for loop

int module = 0;

for(char c: pat) module = (module + (c - 'a')) % (pat.length);

for(int i=0; i<n; ++i) {

}

}

}