C 解法, 执行用时: 1ms, 内存消耗: 256KB, 提交时间: 2020-07-07

#include "stdio.h"
int main()
{
    int n,a,b,i=0,num[1000]={0};
    while(scanf("%d",&n)!= EOF )
    {
        for(i=0;i<n;i++)
        {
        scanf("%d %d",&a,&b);
        num[a]+=b;
        }
        for(i=0;i<n;i++)
        {
            if(num[i]==0)
                continue;
            else
                printf("%d %d\n",i,num[i]);
        }
    }
    return 0; 
}

Pascal 解法, 执行用时: 1ms, 内存消耗: 256KB, 提交时间: 2020-02-29

var
    arr: array[0..1000] of Integer;
    i, iCount, iKey, iValue: Integer;
begin
    while not Eof do
    begin
        readln(iCount);
        if iCount > 0 then
        begin
            //for i := 0 to length(arr) do
            //    arr[i] := 0;
            fillchar(arr, sizeof(arr), 0);    
            for i := 1 to iCount do
            begin
                readln(iKey, iValue);
                arr[iKey] := arr[iKey] + iValue;
            end;
            
            for i := 0 to length(arr) - 1 do
                if arr[i] <> 0 then
                    writeln(i, ' ', arr[i]);
        end;
    end;
end.