Created
February 1, 2021 09:24
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セグメント木によるRMQの実装
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class SegTree(val _n: Int){ | |
val n: Int | |
val d: IntArray | |
init{ | |
var i = 1 | |
while(i < _n) i *= 2 | |
n = i | |
d = IntArray(2 * n - 1){Int.MAX_VALUE} | |
} | |
fun update(k: Int, x: Int){ | |
var k = k + n - 1 | |
d[k] = x | |
while(k > 0){ | |
k = (k - 1) / 2 | |
d[k] = minOf(d[k * 2 + 1], d[k * 2 + 2]) | |
} | |
} | |
fun query(a: Int, b: Int, k: Int, l: Int = 0, r: Int = n): Int{ | |
if(r <= a || b <= l) return Int.MAX_VALUE | |
if(a <= l && r <= b) return d[k] | |
return minOf( | |
query(a, b, k * 2 + 1, l, (l + r) / 2), | |
query(a, b, k * 2 + 2, (l + r) / 2, r) | |
) | |
} | |
fun dump(){ | |
var i = 0 | |
while(1.shl(i) <= n){ | |
println(d.drop(1.shl(i)-1).take(1.shl(i)).joinToString()) | |
i++ | |
} | |
} | |
} | |
fun main(){ | |
val N = readInt() | |
val A = readInts() | |
val Q = readInt() | |
val st = SegTree(N) | |
for((i, a) in A.withIndex()){ | |
st.update(i, a) | |
} | |
st.dump() | |
repeat(Q){ | |
val q = readInts() | |
if(q[0] == 1){ | |
val(_, l, r) = q | |
println(st.query(l, r, 0)) | |
} else { | |
val(_, k, x) = q | |
st.update(k, x) | |
} | |
} | |
} | |
/* | |
8 | |
5 3 7 9 6 4 1 2 | |
7 | |
1 0 5 | |
2 0 2 | |
1 0 5 | |
2 0 -1 | |
1 0 3 | |
1 4 7 | |
1 0 7 | |
*/ | |
val br = System.`in`.bufferedReader() | |
fun readLine() = br.readLine()!! | |
fun readInt() = readLine().toInt() | |
fun readInts() = readLine().split(" ").map(String::toInt) | |
fun readLong() = readLine().toLong() | |
fun readLongs() = readLine().split(" ").map(String::toLong) | |
fun <T>printAll(a: Iterable<T>) = println(a.joinToString("\n")) |
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