用lua从写一次最大子数组问题

这回由于Lua 的语法比较强大，所以直接写出代码 别的不多说了，我们可以看到lua写这种逻辑是多么有快感。可以返回多个值，使算法看起来是这么的自然。

附上源代码：

function FIND_CROSSING_SUBARRAY (A,low,mid,high)
local left_sum = -10000;
local sum = 0;
local max_left;

local i;
for i= mid,low,-1 do
sum = sum + A[i];
if sum>left_sum then
left_sum = sum;
max_left = i;
end
end

local right_sum = -10000;
local sum = 0;
local max_right;

for j = (mid+1),high,1 do
sum = sum + A[j];
if sum >right_sum then
right_sum = sum;
max_right = j;
end
end
return max_left,max_right,left_sum+right_sum
end

function FIND_MAXIMUM_SUBARRAY (A,low,high)

if high == low then
return low,high,A[low]
else
local mid = math.floor((low+high)/2);

local left_low,left_high,left_sum = FIND_MAXIMUM_SUBARRAY(A,low,mid);

local right_low,right_high,right_sum= FIND_MAXIMUM_SUBARRAY(A,mid+1,high);

local cross_low,cross_high,cross_sum= FIND_CROSSING_SUBARRAY(A,low,mid,high);

if left_sum>=right_sum then
if left_sum>=cross_sum then
return left_low,left_high,left_sum
end
end

if(right_sum>=left_sum)then
if (right_sum>=cross_sum) then
return right_low,right_high,right_sum
end
end

return cross_low,cross_high,cross_sum
end
end

B={-100,79,89,201,-211,98,99,201,304,-432};
local left,right,maxvalue= FIND_MAXIMUM_SUBARRAY(B,1,10);
print(left," ",right," ",maxvalue);