xxxxxxxxxx
var items1 = new int[][]
{
new int[]{1,1},
new int[]{4,5},
new int[]{3,8}};
var items2 = new int[][]
{
new int[]{3,1},
new int[]{1,5}
}
;
var merge =items1.Union(items2)
.Select( x => new { Key = x[0], Count = x[1] })
.GroupBy( x => x.Key, (key, value) => new
{
Key = key,
Value = value.Sum(y => y.Count)
});
final answer
Key Value
1 :6
4 :5
3 :9