Longest Substring of One Repeating Character
<p>You are given a <strong>0-indexed</strong> string <code>s</code>. You are also given a <strong>0-indexed</strong> string <code>queryCharacters</code> of length <code>k</code> and a <strong>0-indexed</strong> array of integer <strong>indices</strong> <code>queryIndices</code> of length <code>k</code>, both of which are used to describe <code>k</code> queries.</p>

<p>The <code>i<sup>th</sup></code> query updates the character in <code>s</code> at index <code>queryIndices[i]</code> to the character <code>queryCharacters[i]</code>.</p>

<p>Return <em>an array</em> <code>lengths</code> <em>of length </em><code>k</code><em> where</em> <code>lengths[i]</code> <em>is the <strong>length</strong> of the <strong>longest substring</strong> of </em><code>s</code><em> consisting of <strong>only one repeating</strong> character <strong>after</strong> the</em> <code>i<sup>th</sup></code> <em>query</em><em> is performed.</em></p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;babacc&quot;, queryCharacters = &quot;bcb&quot;, queryIndices = [1,3,3]
<strong>Output:</strong> [3,3,4]
<strong>Explanation:</strong> 
- 1<sup>st</sup> query updates s = &quot;<u>b<strong>b</strong>b</u>acc&quot;. The longest substring consisting of one repeating character is &quot;bbb&quot; with length 3.
- 2<sup>nd</sup> query updates s = &quot;bbb<u><strong>c</strong>cc</u>&quot;. 
  The longest substring consisting of one repeating character can be &quot;bbb&quot; or &quot;ccc&quot; with length 3.
- 3<sup>rd</sup> query updates s = &quot;<u>bbb<strong>b</strong></u>cc&quot;. The longest substring consisting of one repeating character is &quot;bbbb&quot; with length 4.
Thus, we return [3,3,4].
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;abyzz&quot;, queryCharacters = &quot;aa&quot;, queryIndices = [2,1]
<strong>Output:</strong> [2,3]
<strong>Explanation:</strong>
- 1<sup>st</sup> query updates s = &quot;ab<strong>a</strong><u>zz</u>&quot;. The longest substring consisting of one repeating character is &quot;zz&quot; with length 2.
- 2<sup>nd</sup> query updates s = &quot;<u>a<strong>a</strong>a</u>zz&quot;. The longest substring consisting of one repeating character is &quot;aaa&quot; with length 3.
Thus, we return [2,3].
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
	<li><code>k == queryCharacters.length == queryIndices.length</code></li>
	<li><code>1 &lt;= k &lt;= 10<sup>5</sup></code></li>
	<li><code>queryCharacters</code> consists of lowercase English letters.</li>
	<li><code>0 &lt;= queryIndices[i] &lt; s.length</code></li>
</ul>
Segment Tree; Array; String; Ordered Set
class Node {
    l: number;
    r: number;
    lmx: number;
    rmx: number;
    mx: number;

    constructor(l: number, r: number) {
        this.l = l;
        this.r = r;
        this.lmx = 1;
        this.rmx = 1;
        this.mx = 1;
    }
}

class SegmentTree {
    private s: string[];
    private tr: Node[];

    constructor(s: string) {
        this.s = s.split('');
        this.tr = Array(s.length * 4)
            .fill(null)
            .map(() => new Node(0, 0));
        this.build(1, 1, s.length);
    }

    private build(u: number, l: number, r: number): void {
        this.tr[u] = new Node(l, r);
        if (l === r) {
            return;
        }
        const mid = (l + r) >> 1;
        this.build(u << 1, l, mid);
        this.build((u << 1) | 1, mid + 1, r);
        this.pushup(u);
    }

    public modify(u: number, x: number, v: string): void {
        if (this.tr[u].l === x && this.tr[u].r === x) {
            this.s[x - 1] = v;
            return;
        }
        const mid = (this.tr[u].l + this.tr[u].r) >> 1;
        if (x <= mid) {
            this.modify(u << 1, x, v);
        } else {
            this.modify((u << 1) | 1, x, v);
        }
        this.pushup(u);
    }

    public query(u: number, l: number, r: number): number {
        if (this.tr[u].l >= l && this.tr[u].r <= r) {
            return this.tr[u].mx;
        }
        const mid = (this.tr[u].l + this.tr[u].r) >> 1;
        let ans = 0;
        if (r <= mid) {
            ans = this.query(u << 1, l, r);
        } else if (l > mid) {
            ans = Math.max(ans, this.query((u << 1) | 1, l, r));
        } else {
            ans = Math.max(this.query(u << 1, l, r), this.query((u << 1) | 1, l, r));
        }
        return ans;
    }

    private pushup(u: number): void {
        const root = this.tr[u];
        const left = this.tr[u << 1];
        const right = this.tr[(u << 1) | 1];
        root.mx = Math.max(left.mx, right.mx);
        root.lmx = left.lmx;
        root.rmx = right.rmx;
        const a = left.r - left.l + 1;
        const b = right.r - right.l + 1;
        if (this.s[left.r - 1] === this.s[right.l - 1]) {
            if (left.lmx === a) {
                root.lmx += right.lmx;
            }
            if (right.rmx === b) {
                root.rmx += left.rmx;
            }
            root.mx = Math.max(root.mx, left.rmx + right.lmx);
        }
    }
}

function longestRepeating(s: string, queryCharacters: string, queryIndices: number[]): number[] {
    const tree = new SegmentTree(s);
    const k = queryIndices.length;
    const ans: number[] = new Array(k);
    const n = s.length;
    for (let i = 0; i < k; ++i) {
        const x = queryIndices[i] + 1;
        const v = queryCharacters[i];
        tree.modify(1, x, v);
        ans[i] = tree.query(1, 1, n);
    }
    return ans;
}
