int main()
{
FILE *fp = NULL;
int a = 0, b = 0, t, i = 0;
time_t startTime, finishTime;
if ((fp = fopen("testdata.txt", "r")) == NULL) return 0;
fscanf(fp, "%d", &t);
if (t > MAX) t = MAX;
while (t--)
{
fscanf(fp, "%d", &arr[i]);
i++;
}
fclose(fp);
startTime = clock();
printf("%d\n",maxSubsequenceSum(0, MAX));
finishTime = clock();
fp = fopen("result.txt", "a");
if (fp == NULL)
{
fp = fopen("result.txt", "w");
fprintf(fp, "counter : %lld ,data : %ld , runtime %ld ms\n", count, MAX, finishTime-startTime);
fclose(fp);
}
fprintf(fp, "counter : %lld ,data : %ld , runtime %ld ms\n", count, MAX, finishTime - startTime);
fclose(fp);
return 0;
}
int maxSubsequenceSum(int A[], int left, int right)
{
/* maxLeftSum左半部分最大和，maxLeftBorderSum左半边界（带左半最右边元素如A[3]）最大和，leftBorderSum左半边界和 */
int maxLeftSum, maxRightSum;
int maxLeftBorderSum, maxRightBorderSum;
int leftBorderSum ,rightBorderSum;
int center, i;
if(left == right)
if(A[left] > 0)
return A[left];
else
return 0;
center = (left + right) / 2; /* 向下取整 */
maxLeftSum = maxSubsequenceSum(A, left, center); /* 左半最大子序列和 */
maxRightSum = maxSubsequenceSum(A, center + 1, right);
maxLeftBorderSum = 0; /* 左半边界最大和 */
leftBorderSum = 0; /* 左半边界和 */
for(i = center; i >= left; i--)
{ /* 这里貌似用了方法二种的遍历方式，起点是center， end是左半首元素 */
leftBorderSum += A[i];
if(leftBorderSum > maxLeftBorderSum)
maxLeftBorderSum = leftBorderSum;
}
/* 同理 */
maxRightBorderSum = 0;
rightBorderSum = 0;
for(i = center + 1; i <= right; i++)
{ /* 这里貌似用了方法二种的遍历方式，起点是center + 1， end是右半末元素 */
rightBorderSum += A[i];
if(rightBorderSum > maxRightBorderSum)
maxRightBorderSum = rightBorderSum;
}
/* 求左半最大，右半最大，（左半边界最大+右半边界最大）的最大者 */
return max3(maxLeftSum, maxRightSum, maxLeftBorderSum + maxRightBorderSum);
}
int maxSubsequenceSum(int start, int end){
if (start == end){
return arr[start] > 0 ? arr[start] : 0;
}
int center = (start + end) / 2;
int maxLeftSum = maxSubsequenceSum(start, center);
int maxRightSum = maxSubsequenceSum(center + 1, end);
int maxLeftCenterSum = 0;
int maxRightCenterSum = 0;
int leftCenterSum = 0;
int rightCenterSum = 0;
for (int i = center; i >= start; --i)
{
leftCenterSum += arr[i]; // basic operation
count++;
if (leftCenterSum > maxLeftCenterSum)
maxLeftCenterSum = leftCenterSum;
}
for (int i = center + 1; i <= end; ++i)
{
rightCenterSum += arr[i]; // basic operation
count++;
if (rightCenterSum > maxRightCenterSum)
maxRightCenterSum = rightCenterSum;
}
int max = maxLeftSum;
if (maxRightSum>max)
max = maxRightSum;
if (maxLeftCenterSum + maxRightCenterSum > max)
max = maxLeftCenterSum + maxRightCenterSum;
return max;
}
int main(int argc, char *argv[]){
int seq[] = {5, 6, 4, -5, 7, -3, 12, -5, 8, 5}, LEN = 10;
printf("MAX SUM=%d\n", maxSubsequenceSum(seq, LEN));
printf("MAX SUM=%d\n", maxSubsequenceSum2(seq, LEN));
printf("MAX SUM=%d\n", maxSubsequenceSum3(seq, LEN));
printf("MAX SUM=%d\n", maxSubsequenceSum4(seq, LEN));
printf("MIN SUM=%d\n", minSubsequenceSum(seq, LEN));
printf("MIN PSUM=%d\n", minPosSubsequenceSum(seq, LEN));
printf("MIN PSUM=%d\n", minPosSubsequenceSum2(seq, LEN));
printf("MAX MUL=%d\n", maxSubsequenceMul(seq, LEN));
printf("MAX MUL=%d\n", maxSubsequenceMul2(seq, LEN));
return 0 ;
}
int main()
{
FILE *fp =NULL;
time_t start_time, finish_time, h, m, s;
int a = 0, b = 0, t, i = 0;
if ((fp = fopen("testdata.txt", "r")) == NULL) return 0;
fscanf(fp, "%d", &t);
if (t > MAX) t = MAX;
while (t--)
{
fscanf(fp, "%d", &arr[i]);
i++;
}
fclose(fp);
time(&start_time);
printf("MAX VALUE : %d\n",maxSubsequenceSum(MAX, &a, &b));
time(&finish_time);
h = (finish_time - start_time) / 3600;
m = ((finish_time - start_time) - (h * 3600)) / 60;
s = (finish_time - start_time) - ((h * 3600) + (m * 60));
fp = fopen("result.txt", "a");
if (fp == NULL)
{
fp = fopen("result.txt", "w");
fprintf(fp, "data : %ld , runtime %lldh:%lldm:%llds\n",MAX, h, m, s);
fclose(fp);
}
fprintf(fp, "data : %ld , runtime %lldh:%lldm:%llds\n",MAX, h, m, s);
fclose(fp);
return 0;
}
main()
{
int N = 8, maxSum = 0;
char p[256];
char *str = p;
ElementType A[] = {4, -3, 5, -2, -1, 2, 6, -2};
printf("\t ========== [third method-devide and conquer] test for maximum sum of subsequence ==========\n\n");
str = "initial array A: ";
printf("%50s",str);
printArray(A, N);
str = "after computing maximum sum of subsequence: ";
printf("%50s", str);
maxSum = maxSubsequenceSum(A, 0, N-1);
printArray(A, N);
str = "maximum sum of array subsequence is: ";
printf("%50s", str);
printf("%4d\n\n", maxSum);
return 0;
}
