Stable market

Sometimes, the stability of a stock market is at least as important as rapid price changes. Let a stable block be a maximal consecutive block of days with same stock prices. Moreover, let a stable block of order K be a stable block of length at least K. For example, if stock prices for 7 consecutive days are: 20, 10, 10, 7, 7, 7, 10, then there are 4 stable blocks there: [20], [10, 10], [7, 7,