equi_leader() {
    local -n _a="$1"
    local _leaderSize=0 _value=0 _leaderCount=0
    local _k _v
    for _k in "${!_a[@]}"; do
        _v=${_a[$_k]}
        if (( _leaderSize == 0 )); then
            ((_leaderSize++))
            _value=$_v
        elif (( _value != _v )); then
            ((_leaderSize--))
        else
            ((_leaderSize++))
        fi
    done
    local _candidate
    if (( _leaderSize > 0 )); then _candidate=$_value; else _candidate=-1; fi
    _leaderCount=0
    for _v in "${_a[@]}"; do
        if (( _v == _candidate )); then ((_leaderCount++)); fi
    done
    local _leader=-1
    local _count=${#_a[@]}
    if (( 2 * _leaderCount > _count )); then
        _leader=$_candidate
    fi
    local _lLeaderCount=0 _equiLeaders=0
    for _k in "${!_a[@]}"; do
        _v=${_a[$_k]}
        local _leftHalf=$(( (_k + 1) / 2 ))
        local _rightHalf=$(( (_count - _k - 1) / 2 ))
        if (( _v == _leader )); then
            ((_lLeaderCount++))
        fi
        local _rLeaderCount=$(( _leaderCount - _lLeaderCount ))
        if (( _lLeaderCount > _leftHalf && _rLeaderCount > _rightHalf )); then
            ((_equiLeaders++))
        fi
    done
    echo "$_equiLeaders"
}