1、离散化

AcWing 802. 区间和

import java.util.*;

//ACWing
public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.qujianhe();
    }

    //离散化
    class Operate implements Comparable {
        int x, c;

        public Operate(int x, int c) {
            this.x = x;
            this.c = c;
        }

        @Override
        public int compareTo(Object o) {
            Operate operate = (Operate) o;
            if (x == operate.x)
                return c - operate.c;
            else
                return x - operate.x;
        }
    }

    int find(int[] a, int len, int value) {
        int l = 0, r = len - 1;
        while (l < r) {
            int mid = (l + r + 1) / 2;
            if (a[mid] <= value) {
                l = mid;
            } else {
                r = mid - 1;
            }
        }
        return l;
    }

    int find_min(int[] a, int len, int value) {
        int l = 0, r = len - 1;
        while (l < r) {
            int mid = (l + r + 1) / 2;
            if (a[mid] < value) {
                l = mid;
            }
            if (a[mid] >= value) {
                r = mid - 1;
            }
        }
        return l;
    }

    void qujianhe() {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        TreeSet<Operate> treeSet = new TreeSet<Operate>();
        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            int c = sc.nextInt();
            treeSet.add(new Operate(x, c));
        }
        int a[] = new int[n];
        int d[] = new int[n];
        int sum[] = new int[n];
        int len = 0;
        for (Operate operate : treeSet) {
            a[len] = operate.x;
            d[len++] = operate.c;
        }
        for (int i = 0; i < sum.length; i++) {
            if (i == 0)
                sum[i] = d[i];
            else
                sum[i] = sum[i - 1] + d[i];
        }
        for (int i = 0; i < m; i++) {
            int l = sc.nextInt();
            int r = sc.nextInt();
            int ll = find_min(a, len, l);
            int lr = find(a, len, r);
            if (a[0]>=l&&a[0]<=r)
                System.out.println(sum[lr]);
            else
                System.out.println(sum[lr] - sum[ll]);
        }
    }
}