Update 1157-online-majority-element-in-subarray.js

Author: everthis

1157-online-majority-element-in-subarray.js

@@ -1,3 +1,141 @@
+function Bisect() {
+  return { insort_right, insort_left, bisect_left, bisect_right }
+  function insort_right(a, x, lo = 0, hi = null) {
+    lo = bisect_right(a, x, lo, hi)
+    a.splice(lo, 0, x)
+  }
+  function bisect_right(a, x, lo = 0, hi = null) {
+    if (lo < 0) throw new Error('lo must be non-negative')
+    if (hi == null) hi = a.length
+    while (lo < hi) {
+      let mid = (lo + hi) >> 1
+      x < a[mid] ? (hi = mid) : (lo = mid + 1)
+    }
+    return lo
+  }
+  function insort_left(a, x, lo = 0, hi = null) {
+    lo = bisect_left(a, x, lo, hi)
+    a.splice(lo, 0, x)
+  }
+  function bisect_left(a, x, lo = 0, hi = null) {
+    if (lo < 0) throw new Error('lo must be non-negative')
+    if (hi == null) hi = a.length
+    while (lo < hi) {
+      let mid = (lo + hi) >> 1
+      a[mid] < x ? (lo = mid + 1) : (hi = mid)
+    }
+    return lo
+  }
+}
+
+function SegmentTreeRQ(m, A, n) {
+  let bisect = new Bisect()
+  let h = Math.ceil(Math.log2(n))
+  const MAX = 2 * 2 ** h - 1
+  let tree = Array(MAX).fill(-1)
+  let a = [...A]
+  build(1, 0, n - 1)
+  return {
+    query,
+  }
+
+  function build(vi, tl, tr) {
+    if (tl == tr) {
+      tree[vi] = a[tl]
+      return
+    }
+    let mid = getMid(tl, tr)
+    build(vi * 2, tl, mid)
+    build(vi * 2 + 1, mid + 1, tr)
+    if (
+      tree[vi * 2] != -1 &&
+      get_occurrence(tree[vi * 2], tl, tr) * 2 > tr - tl + 1
+    ) {
+      tree[vi] = tree[vi * 2]
+    } else if (
+      tree[vi * 2 + 1] != -1 &&
+      get_occurrence(tree[vi * 2 + 1], tl, tr) * 2 > tr - tl + 1
+    ) {
+      tree[vi] = tree[vi * 2 + 1]
+    }
+  }
+
+  function query(vi, l, r, tl, tr) {
+    if (l > tr || r < tl) {
+      return {
+        first: -1,
+        second: -1,
+      }
+    }
+    if (tl <= l && r <= tr) {
+      if (tree[vi] == -1)
+        return {
+          first: -1,
+          second: -1,
+        }
+      let occ = get_occurrence(tree[vi], tl, tr)
+      if (occ * 2 > tr - tl + 1) {
+        return {
+          first: tree[vi],
+          second: occ,
+        }
+      } else {
+        return {
+          first: -1,
+          second: -1,
+        }
+      }
+    }
+    let mid = getMid(l, r)
+    let resL = query(vi * 2, l, mid, tl, tr)
+    if (resL.first > -1) return resL
+    let resR = query(vi * 2 + 1, mid + 1, r, tl, tr)
+    if (resR.first > -1) return resR
+    return {
+      first: -1,
+      second: -1,
+    }
+  }
+
+  function get_occurrence(num, l, r) {
+    // only difference
+    if (!m.has(num)) return 0
+    let a = m.get(num)
+    let lbv = bisect.bisect_left(a, l) //lower_bound
+    if (lbv == a.length) return 0
+    let ubv = bisect.bisect_right(a, r) // upper_bound
+    return ubv - lbv
+  }
+
+  function getMid(low, high) {
+    return low + ((high - low) >> 1)
+  }
+}
+
+function MajorityChecker(a) {
+  let m = new Map()
+  let n = a.length
+  for (let i = 0; i < n; i++) {
+    if (!m.has(a[i])) m.set(a[i], [])
+    m.get(a[i]).push(i)
+  }
+  let st = new SegmentTreeRQ(m, a, n)
+  return {
+    query,
+  }
+
+  function query(left, right, threshold) {
+    let res = st.query(1, 0, n - 1, left, right)
+    if (res.second >= threshold) {
+      return res.first
+    }
+    return -1
+  }
+}
+
+// another
+
+
 /**
  * @param {number[]} arr
  */