Go

package main

import (
    "bufio"
    "fmt"
    "os"
    "sort"
)

func getKeys(m map[int]int) []int {
    keys := make([]int, 1, len(m)+1)
    for k := range m {
        keys = append(keys, k)
    }
    return keys
}

func lowerBound(values []int, v int) int {
    low, high := 1, len(values)-1
    if v > values[high] {
        return high+1
    }

    for low < high {
        mid := (low + high) / 2
        if values[mid] < v {
            low = mid + 1
        } else {
            high = mid
        }
    }

    return low
}

func upperBound(values []int, v int) int {
    low, high := 1, len(values)-1
    if v < values[low] {
        return low-1
    }

    for low < high {
        mid := (low + high + 1) / 2
        if values[mid] > v {
            high = mid - 1
        } else {
            low = mid
        }
    }

    return high
}

func main() {
    in := bufio.NewReader(os.Stdin)
    var n, m int
    fmt.Fscan(in, &n, &m)

    cup := make(map[int]int)
    for i := 0; i < n; i++ {
        var x, c int
        fmt.Fscan(in, &x, &c)
        cup[x] += c
    }

    keys := getKeys(cup)
    sort.Ints(keys[1:])
    sums := make([]int, len(keys))
    for i := 1; i < len(sums); i++ {    
        sums[i] = sums[i-1] + cup[keys[i]]
    }

    for i := 0; i < m; i++ {
        var l, r int
        fmt.Fscan(in, &l, &r)
        l, r = lowerBound(keys, l), upperBound(keys, r)
        fmt.Println(sums[r] - sums[l-1])
    }
}

C++

#include <iostream>
#include <algorithm>
#include <vector>
#include <unordered_map>
using namespace std;

int lowerBound(const vector<int>& values, int v) {
    int low = 1, high = values.size() - 1;
    if (v > values[high]) {
        return high + 1;
    }

    while (low < high) {
        int mid = (low + high) >> 1;
        if (values[mid] < v) {
            low = mid + 1;
        } else {
            high = mid;
        }
    }

    return low;
}

int upperBound(const vector<int>& values, int v) {
    int low = 1, high = values.size() - 1;
    if (v < values[low]) {
        return low + 1;
    }

    while (low < high) {
        int mid = (low + high + 1) >> 1;
        if (values[mid] > v) {
            high = mid - 1;
        } else {
            low = mid;
        }
    }

    return high;
}

int main() {
    int n, m;
    scanf("%d %d", &n, &m);

    unordered_map<int, int> cup;
    for (int i = 0; i < n; ++i) {
        int x, c;
        scanf("%d %d", &x, &c);
        cup[x] += c;
    }

    vector<int> keys(1, 0);
    for (const auto& p : cup) {
        keys.push_back(p.first);
    }
    sort(keys.begin()+1, keys.end());
    vector<int> sums(keys.size(), 0);
    for (int i = 1; i < sums.size(); ++i) {
        sums[i] = sums[i-1] + cup[keys[i]];
    }

    for (int i = 0; i < m; ++i) {
        int l, r;
        scanf("%d %d", &l, &r);
        l = lowerBound(keys, l);
        r = upperBound(keys, r);
        printf("%d\n", sums[r] - sums[l-1]);
    }

    return 0;
}