give string s partition string substring character substre unique that letter appear single substre oncereturn minimum number substring partitionnote character belong exactly substre partition Example 1input s abacabaoutput 4explanationtwo possible partition abacaba abacabait show 4 minimum number substring neededexample 2input s ssssssoutput 6explanationthe valid partition ssssss Constraints1 slength 105s consist english lowercase letter