(2017多校训练第四场)HDU - 6078 Wavel Sequence dp
传送门：点击打开链接定义状态dp[i][j][0]表示以a[i]，b[j]结尾的且为波谷的情况总和，dp[i][j][1] 为波峰。对于某个i，j满足a[i] == b[j]，则dp[i][j][0] = sum(dp[x][y][1]), x a[i]设sum[i-1][y][1] = ∑dp[x][y][1] , x 则dp[i][j][0] = ∑sum[i-1][y]
