Submission #67738124

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

const int N = 5e5 + 5;

int n, T;
struct node {
    int ans, pre, suf, len;
    char lc, rc;
};

node tree[4 * N];
char s[N];

node tg(node a, node b) {
    node t;
    t.len = a.len + b.len;
    t.lc = a.lc;
    t.rc = b.rc;
    t.ans = max(a.ans, b.ans);
    if (a.rc == b.lc) {
        t.ans = max(t.ans, a.suf + b.pre);
    }
    t.pre = a.pre;
    if (a.pre == a.len && a.rc == b.lc) {
        t.pre = a.pre + b.pre;
    }
    t.suf = b.suf;
    if (b.suf == b.len && a.rc == b.lc) {
        t.suf = b.suf + a.suf;
    }
    return t;
}

void build(int v, int tl, int tr) {
    if (tl == tr) {
        tree[v] = {1, 1, 1, 1, s[tl], s[tl]};
        return;
    }
    int tm = (tl + tr) / 2;
    build(v * 2, tl, tm);
    build(v * 2 + 1, tm + 1, tr);
    tree[v] = tg(tree[v * 2], tree[v * 2 + 1]);
}

void update(int v, int tl, int tr, int pos, char c) {
    if (tl == tr) {
        tree[v] = {1, 1, 1, 1, c, c};
        return;
    }
    int tm = (tl + tr) / 2;
    if (pos <= tm) {
        update(v * 2, tl, tm, pos, c);
    } else {
        update(v * 2 + 1, tm + 1, tr, pos, c);
    }
    tree[v] = tg(tree[v * 2], tree[v * 2 + 1]);
}

node query(int v, int tl, int tr, int l, int r) {
    if (l <= tl && tr <= r) {
        return tree[v];
    }
    int tm = (tl + tr) / 2;
    if (r <= tm) {
        return query(v * 2, tl, tm, l, r);
    }
    if (l > tm) {
        return query(v * 2 + 1, tm + 1, tr, l, r);
    }
    node ln = query(v * 2, tl, tm, l, tm);
    node rn = query(v * 2 + 1, tm + 1, tr, tm + 1, r);
    return tg(ln, rn);
}

int main() {
    scanf("%d%d", &n, &T);
    scanf("%s", s);
    build(1, 0, n - 1);
    while (T--) {
        int op;
        scanf("%d", &op);
        if (op == 1) {
            int i;
            char c;
            scanf("%d %c", &i, &c);
            update(1, 0, n - 1, i - 1, c);
        } else {
            int l, r;
            scanf("%d%d", &l, &r);
            node t = query(1, 0, n - 1, l - 1, r - 1);
            printf("%d\n", t.ans);
        }
    }
    return 0;
}

Submission Info

Compile Error

Main.cpp: In function ‘int main()’:
Main.cpp:77:10: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   77 |     scanf("%d%d", &n, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp:78:10: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   78 |     scanf("%s", s);
      |     ~~~~~^~~~~~~~~
Main.cpp:82:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   82 |         scanf("%d", &op);
      |         ~~~~~^~~~~~~~~~~
Main.cpp:86:18: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   86 |             scanf("%d %c", &i, &c);
      |             ~~~~~^~~~~~~~~~~~~~~~~
Main.cpp:90:18: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   90 |             scanf("%d%d", &l, &r);
      |             ~~~~~^~~~~~~~~~~~~~~~

Judge Result