c++ map.count find a number does not exist

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

I have tried to use map in c++, however, it finds 542-863=-321 in dict, so strange.

#include <iostream>
#include <map>
#include <vector>

using namespace std;


vector<int> twoSum(vector<int>& nums, int target) {
vector<int> result;
int len=nums.size();
if(len==0){
    return result;
}

map<int, int> dict;
map<int, int>::iterator iter;

for(int i=0; i<len;i++){
    dict[nums[i]]=i;
    int ss=target-nums[i];
    cout<<ss<<" ";
    int tag=dict.count(ss);
    cout<<tag<<"tag"<<endl;
    if(dict[target-nums[i]]!=i && tag!=0){
        result.push_back(i);
        result.push_back(dict[target-nums[i]]);
        break;
    }



}
cout<<result[0]<<result[1]<<endl;
return result;
}


int main(){
int a[]={230,863,916,585,981,404,316,785,88,12,70,435,384,778,887,755,740,337,86,92,325,422,815,650,920,125,277,336,221,847,168,23,677,61,400,136,874,363,394,199,863,997,794,587,124,321,212,957,764,173,314,422,927,783,930,282,306,506,44,926,691,568,68,730,933,737,531,180,414,751,28,546,60,371,493,370,527,387,43,541,13,457,328,227,652,365,430,803,59,858,538,427,583,368,375,173,809,896,370,789};
cout<<sizeof(a)/sizeof(a[0])<<endl;
vector<int> nums(a, a+100);

twoSum(nums, 542);
}

output [40,0]

expect [28,45]