#include <bits/stdc++.h>
using namespace std;
int n;
char state[300005];
set<int> setBlock[300005];
vector<int> vectorBlock[300005];
vector<int> FT[300005];
/**
* Build the (compressed) fenwick tree
*/
void build(int l, int r){
for(int i = l; i > 0; i -= i & -i){
setBlock[i].insert(r);
}
}
void finalizeBuild(int n){
for(int i = 1; i <= n; i++){
setBlock[i].insert(1);
setBlock[i].insert(n);
for(int x : setBlock[i]){
vectorBlock[i].push_back(x);
FT[i].push_back(0);
}
FT[i].push_back(0);
}
}
void add(int l, int r, int x){
for(int i = l; i <= n; i += i & -i){
int st = lower_bound(vectorBlock[i].begin(), vectorBlock[i].end(), r) - vectorBlock[i].begin() + 1;
for(int j = st; j <= vectorBlock[i].size(); j += j & -j){
FT[i][j] += x;
}
}
}
int sum(int l, int r){
int ret = 0;
for(int i = l; i > 0; i -= i & -i){
int st = lower_bound(vectorBlock[i].begin(), vectorBlock[i].end(), r) - vectorBlock[i].begin() + 1;
assert(vectorBlock[i][st-1] == r);
for(int j = st; j > 0; j -= j & -j){
ret += FT[i][j];
}
}
return ret;
}
vector<tuple<char,int,int> > queries;
// Helpers
int seg[1048576];
int lb[1048576];
int rb[1048576];
void hBuild(int c, int l, int r){
lb[c] = l;
rb[c] = r;
seg[c] = -1;
if(l == r) return;
int k = (l+r)/2;
hBuild(2*c, l, k);
hBuild(2*c+1, k+1, r);
}
void hUpdate(int c, int l, int r, int x){
if(l > r) return;
if(lb[c] == l && rb[c] == r){
seg[c] = x;
return;
}
int k = (lb[c] + rb[c])/2;
if(l <= k && k < r){
hUpdate(2*c, l, k, x);
hUpdate(2*c+1, k+1, r, x);
}else if(r <= k){
hUpdate(2*c, l, r, x);
}else{
hUpdate(2*c+1, l, r, x);
}
}
int hQuery(int c, int l, int r){
if(seg[c] > seg[2*c]) seg[2*c] = seg[c];
if(seg[c] > seg[2*c+1]) seg[2*c+1] = seg[c];
if(lb[c] == l && rb[c] == r) return seg[c];
int k = (lb[c] + rb[c])/2;
if(l <= k && k < r){
return max(hQuery(2*c, l, k), hQuery(2*c+1, k+1, r));
}else if(r <= k){
return hQuery(2*c, l, r);
}else{
return hQuery(2*c+1, l, r);
}
}
int qidx;
int hFT[300005];
void hAdd(int idx, int amt){
while(idx <= n+1){
hFT[idx] += amt;
idx += idx & -idx;
}
}
int hSum(int idx){
int ret = 0;
while(idx > 0){
ret += hFT[idx];
idx -= idx & -idx;
}
return ret;
}
/**
* Returns the queries index i where i-th query is toggle something in range l, r
* Complexity: O(log N)
* Uses a max-lazy segment tree
*/
int lastProcessed(int l, int r){
return hQuery(1, l, r);
}
/**
* Find rightmost i such that state[i] == 0 but i < x or returns 0 if not exists
* Complexity: O(log^2 N)
* Binary search on fenwick tree
*/
int getRightmostZero(int x){
int lo = 0;
int hi = x-1;
int s = hSum(x-1);
while(lo < hi){
int mid = (lo+hi+1)/2;
if(hSum(mid-1) == s){
hi = mid-1;
}else{
lo = mid;
}
}
return lo;
}
/**
* Find leftmost i such that state[i] == 0 but i > x or returns n+1 if not exists
* Complexity: O(log^2 N)
* Binary search on fenwick tree
*/
int getLeftmostZero(int x){
int lo = x+1;
int hi = n+1;
int s = hSum(x);
while(lo < hi){
int mid = (lo+hi)/2;
if(hSum(mid) == s){
lo = mid+1;
}else{
hi = mid;
}
}
return lo;
}
/**
* Returns whether there are some zeroes in the range l, r ?
* Complexity: O(log^2 N)
*/
bool hasZero(int l, int r){
return getLeftmostZero(l-1) <= r;
}
int query(int l, int r){
if(!hasZero(l, r)){
// if all l -- r is 1,
return sum(l,r) + qidx - lastProcessed(l, r);
}else{
// elif some l -- r is 0
return sum(l,r);
}
}
void toggle(int i){
int l = getRightmostZero(i);
int r = getLeftmostZero(i);
if(state[i] == '1'){
// toggle 1 to 0: find rightmost left 0, leftmost right 0
// let them be l, r
// (all subintervals) stats[l+1][r-1] += i - lastProcessed(l, r)
int d = qidx - lastProcessed(l, r);
add(l+1, 1, d);
add(l+1, r, -d);
}else{
// toggle 0 to 1: find rightmost left 0, leftmost right 0
// let them be l, r
// (all subintervals) stats[l+1][i-1] += i - lastProcessed(l, i)
// (all subintervals) stats[i+1][r-1] += i - lastProcessed(i, r)
int dl = qidx - lastProcessed(l, i);
add(l+1, 1, dl);
add(l+1, i, -dl);
int dr = qidx - lastProcessed(i, r);
add(i+1, 1, dr);
add(i+1, r, -dr);
}
hUpdate(1, l+1, r-1, qidx);
if(state[i] == '0') hAdd(i, -1);
else hAdd(i, 1);
state[i] = '0'+'1'-state[i];
}
int main(){
int q;
scanf("%d%d",&n,&q);
hBuild(1, 0, n+1);
scanf("%s", state+1);
for(int i = 1; i <= n; i++){
if(state[i] == '0') hAdd(i, 1);
}
for(int i = 0; i < q; i++){
char str[32];
int l, r = 0;
scanf("%s%d",str,&l);
if(str[0] == 'q') scanf("%d",&r);
r--;
queries.emplace_back(str[0], l, r);
if(str[0] == 'q') build(l, r);
}
finalizeBuild(n);
for(qidx = 0; qidx < q; qidx++){
char c; int l, r;
tie(c, l, r) = queries[qidx];
if(c == 'q'){
printf("%d\n", query(l, r));
}else{
toggle(l);
}
}
}
Compilation message
street_lamps.cpp: In function 'void add(int, int, int)':
street_lamps.cpp:30:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
30 | for(int j = st; j <= vectorBlock[i].size(); j += j & -j){
| ~~^~~~~~~~~~~~~~~~~~~~~~~~
street_lamps.cpp: In function 'int main()':
street_lamps.cpp:198:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
198 | scanf("%d%d",&n,&q);
| ~~~~~^~~~~~~~~~~~~~
street_lamps.cpp:200:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
200 | scanf("%s", state+1);
| ~~~~~^~~~~~~~~~~~~~~
street_lamps.cpp:207:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
207 | scanf("%s%d",str,&l);
| ~~~~~^~~~~~~~~~~~~~~
street_lamps.cpp:208:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
208 | if(str[0] == 'q') scanf("%d",&r);
| ~~~~~^~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
19 ms |
28544 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
269 ms |
34800 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
21 ms |
28672 KB |
Output is correct |
| 2 |
Correct |
21 ms |
28800 KB |
Output is correct |
| 3 |
Incorrect |
22 ms |
28920 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
22 ms |
28928 KB |
Output is correct |
| 2 |
Correct |
21 ms |
28928 KB |
Output is correct |
| 3 |
Correct |
22 ms |
28800 KB |
Output is correct |
| 4 |
Correct |
21 ms |
28796 KB |
Output is correct |
| 5 |
Runtime error |
3584 ms |
477464 KB |
Execution killed with signal 11 |
| 6 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
19 ms |
28544 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
