Hackpack/SegTree.java at master · ss1237/Hackpack · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
import java.util.*;
import java.io.*;

public class SegTree {
    public static void main(String[] args) throws IOException {
        FastScanner in = new FastScanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int[] nums = new int[] {1, 3, 4, 5, 8, 4, 29, 6, 10, 15, 4, 3, 2};
        ST st = new ST(nums);
        out.println(st.rangeMax(0, 7, 1));
        out.println(st.rangeMin(0, 7, 1));
        out.println(st.rangeSum(0, 7, 1));
        st.rangeInc(22, 1, 4, 1);
        st.rangeInc(-3, 0, 3, 1);
        out.println(st.rangeMax(0, 5, 1));
        out.println(st.rangeMin(0, 5, 1));
        out.println(st.rangeSum(0, 5, 1));

        out.close();

    }

    //Segment Tree implementation for range sum, min, max, and updates
    static class ST {
        int[] left, right, sum, max, min, lazy;
        int n;

        public ST(int[] nums) {
            n = (int) Math.pow(2, Math.ceil(Math.log(nums.length) / Math.log(2)));
            left = new int[2 * n];
            right = new int[2 * n];
            sum = new int[2 * n];
            max = new int[2 * n];
            min = new int[2 * n];
            lazy = new int[2 * n];

            for (int i = 0; i < n; i++) {
                sum[i + n] = (i < nums.length) ? nums[i] : 0;
                max[i + n] = (i < nums.length) ? nums[i] : 0;
                min[i + n] = (i < nums.length) ? nums[i] : 0;
                left[i + n] = i;
                right[i + n] = i;
            }
            for (int i = n - 1; i > 0; i--) {
                sum[i] = sum[i * 2] + sum[i * 2 + 1];
                max[i] = Math.max(max[i * 2], max[i * 2 + 1]);
                min[i] = Math.min(min[i * 2], min[i * 2 + 1]);
                left[i] = left[i * 2];
                right[i] = right[i * 2 + 1];
            }
        }

        int rangeSum(int ll, int rr, int i) {
            if (ll <= left[i] && rr >= right[i]) {
                return sum[i] + lazy[i] * (right[i] - left[i] + 1);
            }
            else if (ll > right[i] || rr < left[i]) {
                return 0;
            }
            else {
                prop(i);
                int left = rangeSum(ll, rr, i * 2);
                int right = rangeSum(ll, rr, i * 2 + 1);
                update(i);

                return left + right;
            }
        }

        int rangeMax(int ll, int rr, int i) {
            if (ll <= left[i] && rr >= right[i]) {
                return max[i];
            }
            else if (ll > right[i] || rr < left[i]) {
                return Integer.MIN_VALUE;
            }
            else {
                prop(i);
                int left = rangeMax(ll, rr, i * 2);
                int right = rangeMax(ll, rr, i * 2 + 1);
                update(i);

                return Math.max(left, right);
            }
        }

        int rangeMin(int ll, int rr, int i) {
            if (ll <= left[i] && rr >= right[i]) {
                return min[i] + lazy[i];
            }
            else if (ll > right[i] || rr < left[i]) {
                return Integer.MAX_VALUE;
            }
            else {
                prop(i);
                int left = rangeMin(ll, rr, i * 2);
                int right = rangeMin(ll, rr, i * 2 + 1);
                update(i);

                return Math.min(left, right);
            }
        }

        void prop(int i) {
            lazy[2 * i] += lazy[i];
            lazy[2 * i + 1] += lazy[i];
            lazy[i] = 0;
        }

        void update(int i) {
            min[i] = Math.min(min[2 * i] + lazy[2 * i], min[2 * i + 1] + lazy[2 * i + 1]);
            max[i] = Math.max(max[2 * i] + lazy[2 * i], max[2 * i + 1] + lazy[2 * i + 1]);

            sum[i] = sum[2 * i] + (right[2 * i] - left[2 * i] + 1) * lazy[2 * i];
            sum[i] += sum[2 * i + 1] + (right[2 * i + 1] - left[2 * i + 1] + 1) * lazy[2 * i + 1];
        }

        void rangeInc(int val, int ll, int rr, int i) {
            if (ll <= left[i] && rr >= right[i]) {
                lazy[i] += val;
            }
            else if (ll > right[i] || rr < left[i]) {
            }
            else {
                prop(i);
                rangeInc(val, ll, rr, 2 * i);
                rangeInc(val, ll, rr, 2 * i + 1);
                update(i);
            }
        }
    }
}