summing-nums.c

#include <stdio.h>

int main() {
    FILE*fin = fopen("input.txt","r");
    FILE*fout = fopen("output.txt","w");
    int N , l, M, r, sum=0;
    fscanf(fin, "%d", &N);
    int A[N+1];
    A[0] = 0;
    for (int i = 1; i <= N ; ++i) {
        fscanf(fin, "%d", &A[i]);
    }
    for (int j = 1; j <= N ; ++j) {
        A[j] = A[j-1] + A[j];
    }
    fscanf(fin, "%d", &M);
    for (int k = 0; k < M; ++k) {
        fscanf(fin, "%d%d", &l, &r);
        fprintf(fout, "%d ", A[r] - A[l-1]);
    }
    fclose(fin);
    fclose(fout);
    return 0;
}